Publications by authors named "Oliver Puk"

47 Publications

Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies.

Am J Med Genet A 2021 May 31;185(5):1366-1378. Epub 2021 Jan 31.

Department of Molecular & Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA.

Neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL), defined primarily by developmental delay/intellectual disability, speech delay, postnatal microcephaly, and dysmorphic features, is a syndrome resulting from heterozygous variants in the dosage-sensitive bromodomain PHD finger chromatin remodeler transcription factor BPTF gene. To date, only 11 individuals with NEDDFL due to de novo BPTF variants have been described. To expand the NEDDFL phenotypic spectrum, we describe the clinical features in 25 novel individuals with 20 distinct, clinically relevant variants in BPTF, including four individuals with inherited changes in BPTF. In addition to the previously described features, individuals in this cohort exhibited mild brain abnormalities, seizures, scoliosis, and a variety of ophthalmologic complications. These results further support the broad and multi-faceted complications due to haploinsufficiency of BPTF.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.62102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048530PMC
May 2021

Imbalances in the eye lens proteome are linked to cataract formation.

Nat Struct Mol Biol 2021 02 11;28(2):143-151. Epub 2021 Jan 11.

Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Technische Universität München, Garching, Germany.

The prevalent model for cataract formation in the eye lens posits that damaged crystallin proteins form light-scattering aggregates. The α-crystallins are thought to counteract this process as chaperones by sequestering misfolded crystallin proteins. In this scenario, chaperone pool depletion would result in lens opacification. Here we analyze lenses from different mouse strains that develop early-onset cataract due to point mutations in α-, β-, or γ-crystallin proteins. We find that these mutant crystallins are unstable in vitro; in the lens, their levels are substantially reduced, and they do not accumulate in the water-insoluble fraction. Instead, all the other crystallin proteins, including the α-crystallins, are found to precipitate. The changes in protein composition and spatial organization of the crystallins observed in the mutant lenses suggest that the imbalance in the lenticular proteome and altered crystallin interactions are the bases for cataract formation, rather than the aggregation propensity of the mutant crystallins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41594-020-00543-9DOI Listing
February 2021

Identification of a New Genetic Mutation Associated With Peters Anomaly.

Cornea 2021 Mar;40(3):373-376

Department of Ophthalmology, University Hospital Tübingen, Tübingen, Germany; and.

Purpose: To report a new genetic mutation in the COL4A1 gene, which was identified in a baby girl with Peters anomaly (PA), a rare anterior segment mesenchymal dysgenesis, which is characterized by unilateral or bilateral corneal opacities often accompanied by glaucoma, cataract, and systemic malformations and associated with various genetic mutations.

Methods: Ophthalmologic examination of one baby girl and whole exome sequencing and Sanger sequencing of blood samples of the child and her biological parents were performed.

Results: Ophthalmologic examination led to the diagnosis of PA type I in the baby girl. Whole exome sequencing and Sanger sequencing identified the de novo mutation c.181_189delinsAGGTTTCCG; p.Gly61Arg in the COL4A1 gene in the child, whereas no other putatively causative variants in established genes associated with anterior segment dysgenesis were present.

Conclusions: PA might be associated with the mutation c.181_189delinsAGGTTTCCG; p.Gly61Arg in the COL4A1 gene. The COL4A1 gene encodes for collagen IVα1, an essential component of basal membranes, and mutations are associated with an increased risk for renal and cerebrovascular disorders and stroke. This should be considered when advising and monitoring patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/ICO.0000000000002611DOI Listing
March 2021

Mutation in Bmpr1b Leads to Optic Disc Coloboma and Ventral Retinal Gliosis in Mice.

Invest Ophthalmol Vis Sci 2020 02;61(2):44

,.

Purpose: The clinical phenotype of retinal gliosis occurs in different forms; here, we characterize one novel genetic feature, (i.e., signaling via BMP-receptor 1b).

Methods: Mouse mutants were generated within a recessive ENU mutagenesis screen; the underlying mutation was identified by linkage analysis and Sanger sequencing. The eye phenotype was characterized by fundoscopy, optical coherence tomography, optokinetic drum, electroretinography, and visual evoked potentials, by histology, immunohistology, and electron-microscopy.

Results: The mutation affects intron 10 of the Bmpr1b gene, which is causative for skipping of exon 10. The expression levels of pSMAD1/5/8 were reduced in the mutant retina. The loss of BMPR1B-mediated signaling leads to optic nerve coloboma, gliosis in the optic nerve head and ventral retina, defective optic nerve axons, and irregular retinal vessels. The ventral retinal gliosis is proliferative and hypertrophic, which is concomitant with neuronal delamination and the reduction of retinal ganglion cells (RGCs); it is dominated by activated astrocytes overexpressing PAX2 and SOX2 but not PAX6, indicating that they may retain properties of gliogenic precursor cells. The expression pattern of PAX2 in the optic nerve head and ventral retina is altered during embryonic development. These events finally result in reduced electrical transmission of the retina and optic nerve and significantly reduced visual acuity.

Conclusions: Our study demonstrates that BMPR1B is necessary for the development of the optic nerve and ventral retina. This study could also indicate a new mechanism in the formation of retinal gliosis; it opens new routes for its treatment eventually preventing scar formation in the retina.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1167/iovs.61.2.44DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7329948PMC
February 2020

MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis.

Brain 2020 01;143(1):55-68

Laboratory of Embryology and Genetics of Human Malformation, Institut National de la Santé et de la Recherche Médicale (INSERM) UMR 1163, Institut Imagine, Paris, France.

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3' region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awz379DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7962909PMC
January 2020

Novel Mutation c.1162_1172del; p.Pro388* in Two Patients with Symptoms of Atypical Rett Syndrome.

Mol Syndromol 2019 Jul 2;10(4):223-228. Epub 2019 Jul 2.

Center of Human Genetics, Jena University Hospital, Jena, Germany.

We report 2 cases of girls with gene variants who do not have typical clinical features of Rett syndrome except for intellectual disability and seizures. Both patients present with adipositas, macrocephalia, precocious puberty, and seizures. They have prominent eyebrows and a short neck as well as short and plump fingers. Sequencing by NGS revealed a novel variant c.1162_1172del; p.Pro388* in both patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000501183DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738185PMC
July 2019

A mouse model for intellectual disability caused by mutations in the X-linked 2'‑O‑methyltransferase Ftsj1 gene.

Biochim Biophys Acta Mol Basis Dis 2019 09 14;1865(9):2083-2093. Epub 2018 Dec 14.

Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Felix-Hausdorff-Strasse 8, 17489 Greifswald, Germany.

Mutations in the X chromosomal tRNA 2'‑O‑methyltransferase FTSJ1 cause intellectual disability (ID). Although the gene is ubiquitously expressed affected individuals present no consistent clinical features beyond ID. In order to study the pathological mechanism involved in the aetiology of FTSJ1 deficiency-related cognitive impairment, we generated and characterized an Ftsj1 deficient mouse line based on the gene trapped stem cell line RRD143. Apart from an impaired learning capacity these mice presented with several statistically significantly altered features related to behaviour, pain sensing, bone and energy metabolism, the immune and the hormone system as well as gene expression. These findings show that Ftsj1 deficiency in mammals is not phenotypically restricted to the brain but affects various organ systems. Re-examination of ID patients with FTSJ1 mutations from two previously reported families showed that several features observed in the mouse model were recapitulated in some of the patients. Though the clinical spectrum related to Ftsj1 deficiency in mouse and man is variable, we suggest that an increased pain threshold may be more common in patients with FTSJ1 deficiency. Our findings demonstrate novel roles for Ftsj1 in maintaining proper cellular and tissue functions in a mammalian organism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbadis.2018.12.011DOI Listing
September 2019

Fgf9 Mutation Alters Information Processing and Social Memory in Mice.

Mol Neurobiol 2018 Jun 10;55(6):4580-4595. Epub 2017 Jul 10.

Institutes of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany.

In neuropsychiatric diseases, such as major depression and anxiety, pathogenic vulnerability is partially dictated by a genetic predisposition. The search continues to define this genetic susceptibility and establish new genetic elements as potential therapeutic targets. The fibroblast growth factors (FGFs) could be interesting in this regard. This family of signaling molecules plays important roles in development while also functioning within the adult. This includes effects on aspects of brain function such as neurogenesis and synapse formation. Of this family, Fgf9 is expressed in the adult brain, but its functional role is less well defined. In this study, we examined the role of Fgf9 in different brain functions by analyzing the behavior of Fgf9 mutant mice, an Fgf9 allele without the confounding systemic effects of other Fgf9 genetic models. Here, we show that this mutation caused altered locomotor and exploratory reactivity to novel, mildly stressful environments. In addition, mutants showed heightened acoustic startle reactivity as well as impaired social discrimination memory. Notably, there was a substantial decrease in the level of adult olfactory bulb neurogenesis with no difference in hippocampal neurogenesis. Collectively, our findings indicate a role for the Fgf9 mutation in information processing and perception of aversive situations as well as in social memory. Thus, genetic alterations in Fgf9 could increase vulnerability to developing neuropsychiatric disease, and we propose the Fgf9 mutant mice as a valuable tool to study the predictive etiological aspects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12035-017-0659-3DOI Listing
June 2018

The First Scube3 Mutant Mouse Line with Pleiotropic Phenotypic Alterations.

G3 (Bethesda) 2016 12 7;6(12):4035-4046. Epub 2016 Dec 7.

German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany

The vertebrate Scube (Signal peptide, CUB, and EGF-like domain-containing protein) family consists of three independent members, Scube1-3, which encode secreted cell surface-associated membrane glycoproteins. Limited information about the general function of this gene family is available, and their roles during adulthood. Here, we present the first Scube3 mutant mouse line (Scube3), which clearly shows phenotypic alterations by carrying a missense mutation in exon 8, and thus contributes to our understanding of SCUBE3 functions. We performed a detailed phenotypic characterization in the German Mouse Clinic (GMC). Scube3 mutants showed morphological abnormalities of the skeleton, alterations of parameters relevant for bone metabolism, changes in renal function, and hearing impairments. These findings correlate with characteristics of the rare metabolic bone disorder Paget disease of bone (PDB), associated with the chromosomal region of human SCUBE3 In addition, alterations in energy metabolism, behavior, and neurological functions were detected in Scube3 mice. The Scube3 mutant mouse line may serve as a new model for further studying the effect of impaired SCUBE3 gene function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1534/g3.116.033670DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5144972PMC
December 2016

Meis1 coordinates a network of genes implicated in eye development and microphthalmia.

Development 2015 Sep 7;142(17):3009-20. Epub 2015 Aug 7.

Centro de Biología Molecular "Severo Ochoa", CSIC-UAM, c/Nicolás Cabrera, 1, Madrid E-28049, Spain CIBER de Enfermedades Raras (CIBERER), c/Nicolás Cabrera, 1, Madrid E-28049, Spain

Microphthalmos is a rare congenital anomaly characterized by reduced eye size and visual deficits of variable degree. Sporadic and hereditary microphthalmos have been associated with heterozygous mutations in genes fundamental for eye development. Yet, many cases are idiopathic or await the identification of molecular causes. Here we show that haploinsufficiency of Meis1, which encodes a transcription factor with evolutionarily conserved expression in the embryonic trunk, brain and sensory organs, including the eye, causes microphthalmic traits and visual impairment in adult mice. By combining analysis of Meis1 loss-of-function and conditional Meis1 functional rescue with ChIP-seq and RNA-seq approaches we show that, in contrast to its preferential association with Hox-Pbx BSs in the trunk, Meis1 binds to Hox/Pbx-independent sites during optic cup development. In the eye primordium, Meis1 coordinates, in a dose-dependent manner, retinal proliferation and differentiation by regulating genes responsible for human microphthalmia and components of the Notch signaling pathway. In addition, Meis1 is required for eye patterning by controlling a set of eye territory-specific transcription factors, so that in Meis1(-/-) embryos boundaries among the different eye territories are shifted or blurred. We propose that Meis1 is at the core of a genetic network implicated in eye patterning/microphthalmia, and represents an additional candidate for syndromic cases of these ocular malformations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1242/dev.122176DOI Listing
September 2015

Analysis of mammalian gene function through broad-based phenotypic screens across a consortium of mouse clinics.

Authors:
Martin Hrabě de Angelis George Nicholson Mohammed Selloum Jacqui White Hugh Morgan Ramiro Ramirez-Solis Tania Sorg Sara Wells Helmut Fuchs Martin Fray David J Adams Niels C Adams Thure Adler Antonio Aguilar-Pimentel Dalila Ali-Hadji Gregory Amann Philippe André Sarah Atkins Aurelie Auburtin Abdel Ayadi Julien Becker Lore Becker Elodie Bedu Raffi Bekeredjian Marie-Christine Birling Andrew Blake Joanna Bottomley Mike Bowl Véronique Brault Dirk H Busch James N Bussell Julia Calzada-Wack Heather Cater Marie-France Champy Philippe Charles Claire Chevalier Francesco Chiani Gemma F Codner Roy Combe Roger Cox Emilie Dalloneau André Dierich Armida Di Fenza Brendan Doe Arnaud Duchon Oliver Eickelberg Chris T Esapa Lahcen El Fertak Tanja Feigel Irina Emelyanova Jeanne Estabel Jack Favor Ann Flenniken Alessia Gambadoro Lilian Garrett Hilary Gates Anna-Karin Gerdin George Gkoutos Simon Greenaway Lisa Glasl Patrice Goetz Isabelle Goncalves Da Cruz Alexander Götz Jochen Graw Alain Guimond Wolfgang Hans Geoff Hicks Sabine M Hölter Heinz Höfler John M Hancock Robert Hoehndorf Tertius Hough Richard Houghton Anja Hurt Boris Ivandic Hughes Jacobs Sylvie Jacquot Nora Jones Natasha A Karp Hugo A Katus Sharon Kitchen Tanja Klein-Rodewald Martin Klingenspor Thomas Klopstock Valerie Lalanne Sophie Leblanc Christoph Lengger Elise le Marchand Tonia Ludwig Aline Lux Colin McKerlie Holger Maier Jean-Louis Mandel Susan Marschall Manuel Mark David G Melvin Hamid Meziane Kateryna Micklich Christophe Mittelhauser Laurent Monassier David Moulaert Stéphanie Muller Beatrix Naton Frauke Neff Patrick M Nolan Lauryl Mj Nutter Markus Ollert Guillaume Pavlovic Natalia S Pellegata Emilie Peter Benoit Petit-Demoulière Amanda Pickard Christine Podrini Paul Potter Laurent Pouilly Oliver Puk David Richardson Stephane Rousseau Leticia Quintanilla-Fend Mohamed M Quwailid Ildiko Racz Birgit Rathkolb Fabrice Riet Janet Rossant Michel Roux Jan Rozman Ed Ryder Jennifer Salisbury Luis Santos Karl-Heinz Schäble Evelyn Schiller Anja Schrewe Holger Schulz Ralf Steinkamp Michelle Simon Michelle Stewart Claudia Stöger Tobias Stöger Minxuan Sun David Sunter Lydia Teboul Isabelle Tilly Glauco P Tocchini-Valentini Monica Tost Irina Treise Laurent Vasseur Emilie Velot Daniela Vogt-Weisenhorn Christelle Wagner Alison Walling Bruno Weber Olivia Wendling Henrik Westerberg Monja Willershäuser Eckhard Wolf Anne Wolter Joe Wood Wolfgang Wurst Ali Önder Yildirim Ramona Zeh Andreas Zimmer Annemarie Zimprich Chris Holmes Karen P Steel Yann Herault Valérie Gailus-Durner Ann-Marie Mallon Steve Dm Brown

Nat Genet 2015 Sep 27;47(9):969-978. Epub 2015 Jul 27.

MRC Harwell, Medical Research Council, Harwell, UK.

The function of the majority of genes in the mouse and human genomes remains unknown. The mouse embryonic stem cell knockout resource provides a basis for the characterization of relationships between genes and phenotypes. The EUMODIC consortium developed and validated robust methodologies for the broad-based phenotyping of knockouts through a pipeline comprising 20 disease-oriented platforms. We developed new statistical methods for pipeline design and data analysis aimed at detecting reproducible phenotypes with high power. We acquired phenotype data from 449 mutant alleles, representing 320 unique genes, of which half had no previous functional annotation. We captured data from over 27,000 mice, finding that 83% of the mutant lines are phenodeviant, with 65% demonstrating pleiotropy. Surprisingly, we found significant differences in phenotype annotation according to zygosity. New phenotypes were uncovered for many genes with previously unknown function, providing a powerful basis for hypothesis generation and further investigation in diverse systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ng.3360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4564951PMC
September 2015

New mutation in the mouse Xpd/Ercc2 gene leads to recessive cataracts.

PLoS One 2015 7;10(5):e0125304. Epub 2015 May 7.

Institutes of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany; German Mouse Clinic, Helmholtz Zentrum München, Neuherberg, Germany.

Cataracts are the major eye disorder and have been associated mainly with mutations in lens-specific genes, but cataracts are also frequently associated with complex syndromes. In a large-scale high-throughput ENU mutagenesis screen we analyzed the offspring of paternally treated C3HeB/FeJ mice for obvious dysmorphologies. We identified a mutant suffering from rough coat and small eyes only in homozygotes; homozygous females turned out to be sterile. The mutation was mapped to chromosome 7 between the markers 116J6.1 and D7Mit294;4 other markers within this interval did not show any recombination among 160 F2-mutants. The critical interval (8.6 Mb) contains 3 candidate genes (Apoe, Six5, Opa3); none of them showed a mutation. Using exome sequencing, we identified a c.2209T>C mutation in the Xpd/Ercc2 gene leading to a Ser737Pro exchange. During embryonic development, the mutant eyes did not show major changes. Postnatal histological analyses demonstrated small cortical vacuoles; later, cortical cataracts developed. Since XPD/ERCC2 is involved in DNA repair, we checked also for the presence of the repair-associated histone γH2AX in the lens. During the time, when primary lens fiber cell nuclei are degraded, γH2AX was strongly expressed in the cell nuclei; later, it demarcates clearly the border of the lens cortex to the organelle-free zone. Moreover, we analyzed also whether seemingly healthy heterozygotes might be less efficient in repair of DNA damage induced by ionizing radiation than wild types. Peripheral lymphocytes irradiated by 1Gy Cs137 showed 6 hrs after irradiation significantly more γH2AX foci in heterozygotes than in wild types. These findings demonstrate the importance of XPD/ERCC2 not only for lens fiber cell differentiation, but also for the sensitivity to ionizing radiation. Based upon these data, we hypothesize that variations in the human XPD/ERCC2 gene might increase the susceptibility for several disorders besides Xeroderma pigmentosum in heterozygotes under particular environmental conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0125304PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4423972PMC
February 2016

Neutralizing IL-17 protects the optic nerve from autoimmune pathology and prevents retinal nerve fiber layer atrophy during experimental autoimmune encephalomyelitis.

J Autoimmun 2015 Jan 1;56:34-44. Epub 2014 Oct 1.

Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Straße 22, 81675 München, Germany; Munich Cluster for Systems Neurology (SyNergy), München, Germany. Electronic address:

Optic neuritis is a common inflammatory manifestation of multiple sclerosis (MS). In experimental autoimmune encephalomyelitis (EAE), the optic nerve is affected as well. Here, we investigated whether autoimmune inflammation in the optic nerve is distinct from inflammation in other parts of the central nervous system (CNS). In our study, inflammatory infiltrates in the optic nerve and the brain were characterized by a high fraction of Ly6G(+) granulocytes whereas in the spinal cord, macrophage infiltrates were predominant. At the peak of disease, IL-17 mRNA abundance was highest in the optic nerve as compared with other parts of the CNS. The ratio of IL-17 vs IFN-γ producing CD4(+) T cells was higher in the optic nerve and brain than in the spinal cord and more effector CD4(+) T cells were committed to the Th17 transcriptional program in the optic nerve than in the spinal cord. IL-17 producing γδ T cells but rather not Ly6G(+) granulocytes themselves contributed to IL-17 production. Optical coherence tomography (OCT) studies on murine eyes revealed a decline in thickness of the retinal nerve fiber layer (RNFL) and the common layer of ganglion cells and inner plexiform layer (GCL+) after the recovery from motor symptoms indicating that autoimmune inflammation induced a significant atrophy of optic nerve fibers during EAE. Neutralization of IL-17 by treatment with anti-IL-17 antibodies reduced but did not abrogate motor symptoms of EAE. However, RNFL and GCL+ atrophy were completely prevented by blocking IL-17. Thus, the optic nerve compartment is particularly prone to support IL-17 mediated inflammatory responses during CNS autoimmunity and structural integrity of the retina can be preserved by neutralizing IL-17.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jaut.2014.09.003DOI Listing
January 2015

Pleiotropic functions for transcription factor zscan10.

PLoS One 2014 11;9(8):e104568. Epub 2014 Aug 11.

Stem Cell and Developmental Biology, Genome Institute of Singapore, Singapore, Singapore.

The transcription factor Zscan10 had been attributed a role as a pluripotency factor in embryonic stem cells based on its interaction with Oct4 and Sox2 in in vitro assays. Here we suggest a potential role of Zscan10 in controlling progenitor cell populations in vivo. Mice homozygous for a Zscan10 mutation exhibit reduced weight, mild hypoplasia in the spleen, heart and long bones and phenocopy an eye malformation previously described for Sox2 hypomorphs. Phenotypic abnormalities are supported by the nature of Zscan10 expression in midgestation embryos and adults suggesting a role for Zscan10 in either maintaining progenitor cell subpopulation or impacting on fate choice decisions thereof.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0104568PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4128777PMC
April 2015

Lens density tracking in mice by Scheimpflug imaging.

Mamm Genome 2013 Aug 9;24(7-8):295-302. Epub 2013 Aug 9.

German Mouse Clinic, Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.

Scheimpflug imaging has recently been established for in vivo imaging of the anterior eye segment and quantitative determination of lens transparency in the mouse. This enables more effective investigations of cataract formation with the mouse model, including longitudinal studies. In order to enable recognition of disease-associated irregularities, we performed Scheimpflug measurements with the common laboratory inbred lines C57BL/6J, C3HeB/FeJ, FVB/NCrl, BALB/cByJ, and 129/SvJ in a period between 2 and 12 months of age. C57BL/6J mice showed lowest mean lens densities during the test period. Progressive cortical lens opacification was generally observed, with the earliest onset in C57BBL/6J, C3HeB/FeJ, and 129/SvJ, between 2 and 6 months after birth. Moreover, lenses of these inbred lines developed nuclear opacities. Calculated mean lens density significantly increased between 6 and 12 months of age in all inbred strains except 129/SvJ. Lens densities (and the corresponding standard deviations) of FVB/NCrl and 129/SvJ increased most likely because of differences in the genetic background. Albinism as confounder might be excluded since the albino Balb/cByJ mice are more similar to the C57BL/6J or C3Heb/FeJ mice. We further identified strain-specific anterior lens opacities (C57BL/6J) and cloudy corneal lesions (C57BL/6J, FVB/NCrl, and BALB/cByJ) at later stages. In conclusion, our results indicate that there are lifelong opacification processes in the mouse lens. The highest lens transparency and a dark coat color, which prevents interference from light reflections, make mice with the C57BL/6J background most suitable for cataract research by Scheimpflug imaging. We show that lens densitometry by Scheimpflug imaging in mouse eyes can resolve differences of less than 1 %, making it possible to detect differences in cataract development in different mouse strains, even if they are small.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00335-013-9470-2DOI Listing
August 2013

A comparative phenotypic and genomic analysis of C57BL/6J and C57BL/6N mouse strains.

Genome Biol 2013 Jul 31;14(7):R82. Epub 2013 Jul 31.

Background: The mouse inbred line C57BL/6J is widely used in mouse genetics and its genome has been incorporated into many genetic reference populations. More recently large initiatives such as the International Knockout Mouse Consortium (IKMC) are using the C57BL/6N mouse strain to generate null alleles for all mouse genes. Hence both strains are now widely used in mouse genetics studies. Here we perform a comprehensive genomic and phenotypic analysis of the two strains to identify differences that may influence their underlying genetic mechanisms.

Results: We undertake genome sequence comparisons of C57BL/6J and C57BL/6N to identify SNPs, indels and structural variants, with a focus on identifying all coding variants. We annotate 34 SNPs and 2 indels that distinguish C57BL/6J and C57BL/6N coding sequences, as well as 15 structural variants that overlap a gene. In parallel we assess the comparative phenotypes of the two inbred lines utilizing the EMPReSSslim phenotyping pipeline, a broad based assessment encompassing diverse biological systems. We perform additional secondary phenotyping assessments to explore other phenotype domains and to elaborate phenotype differences identified in the primary assessment. We uncover significant phenotypic differences between the two lines, replicated across multiple centers, in a number of physiological, biochemical and behavioral systems.

Conclusions: Comparison of C57BL/6J and C57BL/6N demonstrates a range of phenotypic differences that have the potential to impact upon penetrance and expressivity of mutational effects in these strains. Moreover, the sequence variants we identify provide a set of candidate genes for the phenotypic differences observed between the two strains.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/gb-2013-14-7-r82DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053787PMC
July 2013

Rapamycin extends murine lifespan but has limited effects on aging.

J Clin Invest 2013 Aug 25;123(8):3272-91. Epub 2013 Jul 25.

Institute of Pathology, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.

Aging is a major risk factor for a large number of disorders and functional impairments. Therapeutic targeting of the aging process may therefore represent an innovative strategy in the quest for novel and broadly effective treatments against age-related diseases. The recent report of lifespan extension in mice treated with the FDA-approved mTOR inhibitor rapamycin represented the first demonstration of pharmacological extension of maximal lifespan in mammals. Longevity effects of rapamycin may, however, be due to rapamycin's effects on specific life-limiting pathologies, such as cancers, and it remains unclear if this compound actually slows the rate of aging in mammals. Here, we present results from a comprehensive, large-scale assessment of a wide range of structural and functional aging phenotypes, which we performed to determine whether rapamycin slows the rate of aging in male C57BL/6J mice. While rapamycin did extend lifespan, it ameliorated few studied aging phenotypes. A subset of aging traits appeared to be rescued by rapamycin. Rapamycin, however, had similar effects on many of these traits in young animals, indicating that these effects were not due to a modulation of aging, but rather related to aging-independent drug effects. Therefore, our data largely dissociate rapamycin's longevity effects from effects on aging itself.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/JCI67674DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3726163PMC
August 2013

Longitudinal fundus and retinal studies with SD-OCT: a comparison of five mouse inbred strains.

Mamm Genome 2013 Jun 17;24(5-6):198-205. Epub 2013 May 17.

German Mouse Clinic, Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstrasse 1, Neuherberg, Germany.

Spectral domain optical coherence tomography (SD-OCT) has recently been established as a method for in vivo imaging of fundus and retina in the mouse. It enables more effective studies of retinal diseases including investigations of etiopathologic mechanisms. In order to learn more about longitudinal fundus development and to enable recognition of disease-associated irregularities, we performed confocal scanning laser ophthalmoscopy (cSLO) and SD-OCT measurements in the inbred strains C57BL/6J, C3HeB/FeJ, FVB/NCrl, BALB/cByJ, and 129S2/SvJ when they were between 2 and 6 months of age. In general, cSLO and SD-OCT data did not reveal sex-specific or unilateral differences. C3HeB/FeJ and FVB/NCrl mice showed diffuse choroidal dysplasia. Choroidal vein-like structures appeared as dark fundus stripes in C3HeB/FeJ. In FVB/NCrl, fundus fleck accumulation was found. In contrast, only minor time-dependent changes of fundus appearance were observed in C57BL/6J, BALB/cByJ, and 129S2/SvJ. This was also found for individual fundic main blood vessel patterns in all inbred strains. Vessel numbers varied between 6 and 13 in C57BL/6J. This was comparable in most cases. We further found that retinae were significantly thicker in C57BL/6J compared to the other strains. Total retinal thickness generally did not change between 2 and 6 months of age. As a conclusion, our results indicate lifelong pathologic processes in C3HeB/FeJ and FVB/NCrl that affect choroid and orbital tissues. Inbred strains with regular retinal development did not reveal major time-dependent variations of fundus appearance, blood vessel pattern, or retinal thickness. Consequently, progressive changes of these parameters are suitable indicators for pathologic outliers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00335-013-9457-zDOI Listing
June 2013

Novel small-eye allele in paired box gene 6 (Pax6) is caused by a point mutation in intron 7 and creates a new exon.

Mol Vis 2013 12;19:877-84. Epub 2013 Apr 12.

Helmholtz Center Munich, German Research Center for Environmental Health, German Mouse Clinic, Institute of Developmental Genetics, Neuherberg, Germany.

Purpose: Within a mutagenesis screen, we identified the new mouse mutant Aey80 with small eyes; homozygous mutants were not obtained. The aim of the study was its molecular characterization.

Methods: We analyzed the offspring of paternally N-ethyl-N-nitrosourea (ENU)-treated C3HeB/FeJ mice for dysmorphology parameters, which can be observed with the naked eye. The Aey80 mutant (abnormality of the eye) was further characterized with laser interference biometry, Scheimpflug imaging, and optical coherence tomography. Linkage analysis of the Aey80 mutant was performed using a panel of single nucleotide polymorphisms different among C3HeB/FeJ and C57BL/6J mice. The Aey80 mutation was identified with sequence analysis of the positional candidate gene.

Results: We identified a new mutant characterized by an obvious small-eye phenotype; homozygotes are not viable after birth. Embryos at embryonic day 15.5 demonstrate a clear gene-dosage effect: Heterozygotes have small eyes, whereas homozygous mutants do not have eyes. In adult mice, the lenses and the entire eyes of the heterozygous mutants were significantly smaller than those of the wild-types (p<0.01). No other ocular phenotypes were observed; the lenses were fully transparent, and no adhesion to the cornea was observed. The mutation was mapped to chromosome 2; markers between 70.8 MB and 129.5 MB showed significant linkage to the mutation resulting in paired box gene 6 (Pax6) as an excellent candidate gene. We amplified cDNAs from the embryonic eyes and observed an additional band while amplifying the region corresponding to exons 7 and 8. The additional band included an alternative exon of 141 bp, which was associated with a G->A exchange four bases downstream of the end of the alternative exon. The alternative exon in the mutants is predicted to encode 30 novel amino acids and three stop codons. This alternative exon kept the paired domain intact but led to a loss of the homeodomain and the C-terminal proline-serine-threonine (PST) domain. The mutation cosegregated in the mutant line, since all five additional small-eyed mice from this line showed the same mutation. A general polymorphism at the mutated site was excluded with sequence analysis of seven other wild-type mouse strains different from C3HeB/FeJ.

Conclusions: These findings demonstrate a novel allele of the paired box gene 6 (Pax6) that affects lens development in a semidominant manner leading to a classical small-eye phenotype. However, the site of the mutation more than 1 kb downstream of exon 7 and resulting in an alternative exon is quite unusual. It indicates the importance of sequence analysis of cDNA for mutation detection; mutations like this are unlikely to be identified by analyzing genomic sequences only. Moreover, this particular mutation demonstrates how a novel exon can be created by only a single base-pair exchange.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3626302PMC
September 2013

Permanent neonatal diabetes in INS(C94Y) transgenic pigs.

Diabetes 2013 May 28;62(5):1505-11. Epub 2012 Dec 28.

Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany.

Mutations in the insulin (INS) gene may cause permanent neonatal diabetes mellitus (PNDM). Ins2 mutant mouse models provided important insights into the disease mechanisms of PNDM but have limitations for translational research. To establish a large animal model of PNDM, we generated INS(C94Y) transgenic pigs. A line expressing high levels of INS(C94Y) mRNA (70-86% of wild-type INS transcripts) exhibited elevated blood glucose soon after birth but unaltered β-cell mass at the age of 8 days. At 4.5 months, INS(C94Y) transgenic pigs exhibited 41% reduced body weight, 72% decreased β-cell mass (-53% relative to body weight), and 60% lower fasting insulin levels compared with littermate controls. β-cells of INS(C94Y) transgenic pigs showed a marked reduction of insulin secretory granules and severe dilation of the endoplasmic reticulum. Cataract development was already visible in 8-day-old INS(C94Y) transgenic pigs and became more severe with increasing age. Diabetes-associated pathological alterations of kidney and nervous tissue were not detected during the observation period of 1 year. The stable diabetic phenotype and its rescue by insulin treatment make the INS(C94Y) transgenic pig an attractive model for insulin supplementation and islet transplantation trials, and for studying developmental consequences of maternal diabetes mellitus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2337/db12-1065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636654PMC
May 2013

Innovations in phenotyping of mouse models in the German Mouse Clinic.

Mamm Genome 2012 Oct 29;23(9-10):611-22. Epub 2012 Aug 29.

German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstrasse 1, 85764 Neuherberg/Munich, Germany.

Under the label of the German Mouse Clinic (GMC), a concept has been developed and implemented that allows the better understanding of human diseases on the pathophysiological and molecular level. This includes better understanding of the crosstalk between different organs, pleiotropy of genes, and the systemic impact of envirotypes and drugs. In the GMC, experts from various fields of mouse genetics and physiology, in close collaboration with clinicians, work side by side under one roof. The GMC is an open-access platform for the scientific community by providing phenotypic analysis in bilateral collaborations ("bottom-up projects") and as a partner and driver in international large-scale biology projects ("top-down projects"). Furthermore, technology development is a major topic in the GMC. Innovative techniques for primary and secondary screens are developed and implemented into the phenotyping pipelines (e.g., detection of volatile organic compounds, VOCs).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00335-012-9415-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463795PMC
October 2012

Visualizing corticotropin-releasing hormone receptor type 1 expression and neuronal connectivities in the mouse using a novel multifunctional allele.

J Comp Neurol 2012 Oct;520(14):3150-80

Max Planck Institute of Psychiatry, 80804 Munich, Germany.

The corticotropin-releasing hormone (CRH) and its type 1 receptor (CRHR1) play a central role in coordinating the endocrine, autonomic, and behavioral responses to stress. A prerequisite to functionally dissect the complexity of the CRH/CRHR1 system is to unravel the identity of CRHR1-expressing neurons and their connectivities. Therefore, we used a knockin approach to genetically label CRHR1-expressing cells with a tau-lacZ (tZ) reporter gene. The distribution of neurons expressing β-galactosidase in the brain and the relative intensity of labeling is in full accordance with previously described Crhr1 mRNA expression. Combining the microtubule-binding properties of TAU with the Cre-loxP system allowed to direct the β-galactosidase to proximal dendrites, and in particular to axons. Thereby, we were able to visualize projections of CRHR1 neurons such as glutamatergic and dopaminergic afferent connections of the striatum and GABAergic CRHR1-expressing neurons located within its patch compartment. In addition, the tZ reporter gene revealed novel details of CRHR1 expression in the spinal cord, skin, and eye. CRHR1 expression in the retina prompted the identification of a new physiological role of CRHR1 related to the visual system. Besides its reporter properties, this novel CRHR1 allele comprises the possibility to conditionally restore or delete CRHR1 via Flp and Cre recombinase, respectively. Finally, the allele is suitable for further manipulations of the CRHR1 locus by recombinase-mediated cassette exchange. Taken together, this novel mouse allele will significantly facilitate the neuroanatomical analysis of CRHR1 circuits and opens up new avenues to address CRHR1 function in more detail.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cne.23082DOI Listing
October 2012

Visual capabilities and cortical maps in BALB/c mice.

Eur J Neurosci 2012 Sep 28;36(6):2801-11. Epub 2012 Jun 28.

Leibniz-Institut für Neurobiologie, Magdeburg, Germany.

By combining behavioural analyses with intrinsic signal optical imaging, we analysed visual performance and visual cortical activity in the albino mouse strain BALB/c, which is increasingly being used as an animal model of neuropsychological disorders. Visual acuity, as measured by a virtual-reality optomotor system, was 0.12 cycles per degree (cyc/deg) in BALB/c mice and 0.39 cyc/deg in pigmented C57BL/6 mice. Surprisingly, BALB/c mice showed reflexive head movements against the direction of the rotating stimulus. Contrast sensitivity was significantly lower in BALB/c mice (45% contrast at 0.064 cyc/deg) than in C57BL/6 mice (6% contrast). In the visual water task, visual acuity was 0.3 cyc/deg in BALB/c mice and 0.59 cyc/deg in C57BL/6 mice. Thus, the visual performance of BALB/c mice was significantly impaired in both behavioural tests - visual acuity was ∼ 0.3 cyc/deg lower than in C57BL/6 mice, and contrast sensitivity was reduced by a factor of ∼ 8. In BALB/c mice, visual cortical maps induced by stimulation of the contralateral eye were normal in both activation strength and retinotopic map quality. In contrast, maps induced by ipsilateral eye stimulation differed significantly between the strains - activity in a region representing 15° to 19° elevation in the visual field was significantly weaker in BALB/c mice than in C57BL/6 mice. Taken together, our observations show that BALB/c mice, like the albino animals of other species, have a significantly lower visual performance than C57BL/6 mice and a modified cortical representation of the ipsilateral eye that may impair stereopsis. Thus, our results caution against disregarding vision as a confounding factor in behavioural tests of neuropsychological disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1460-9568.2012.08195.xDOI Listing
September 2012

Cytochrome c oxidase subunit 4 isoform 2-knockout mice show reduced enzyme activity, airway hyporeactivity, and lung pathology.

FASEB J 2012 Sep 22;26(9):3916-30. Epub 2012 Jun 22.

Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.

Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial electron transport chain. The purpose of this study was to analyze the function of lung-specific cytochrome c oxidase subunit 4 isoform 2 (COX4i2) in vitro and in COX4i2-knockout mice in vivo. COX was isolated from cow lung and liver as control and functionally analyzed. COX4i2-knockout mice were generated and the effect of the gene knockout was determined, including COX activity, tissue energy levels, noninvasive and invasive lung function, and lung pathology. These studies were complemented by a comprehensive functional screen performed at the German Mouse Clinic (Neuherberg, Germany). We show that isolated cow lung COX containing COX4i2 is about twice as active (88 and 102% increased activity in the presence of allosteric activator ADP and inhibitor ATP, respectively) as liver COX, which lacks COX4i2. In COX4i2-knockout mice, lung COX activity and cellular ATP levels were significantly reduced (-50 and -29%, respectively). Knockout mice showed decreased airway responsiveness (60% reduced P(enh) and 58% reduced airway resistance upon challenge with 25 and 100 mg methacholine, respectively), and they developed a lung pathology deteriorating with age that included the appearance of Charcot-Leyden crystals. In addition, there was an interesting sex-specific phenotype, in which the knockout females showed reduced lean mass (-12%), reduced total oxygen consumption rate (-8%), improved glucose tolerance, and reduced grip force (-14%) compared to wild-type females. Our data suggest that high activity lung COX is a central determinant of airway function and is required for maximal airway responsiveness and healthy lung function. Since airway constriction requires energy, we propose a model in which reduced tissue ATP levels explain protection from airway hyperresponsiveness, i.e., absence of COX4i2 leads to reduced lung COX activity and ATP levels, which results in impaired airway constriction and thus reduced airway responsiveness; long-term lung pathology develops in the knockout mice due to impairment of energy-costly lung maintenance processes; and therefore, we propose mitochondrial oxidative phosphorylation as a novel target for the treatment of respiratory diseases, such as asthma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1096/fj.11-203273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425824PMC
September 2012

Large-scale phenotyping of an accurate genetic mouse model of JNCL identifies novel early pathology outside the central nervous system.

PLoS One 2012 6;7(6):e38310. Epub 2012 Jun 6.

Molecular Neurogenetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America.

Cln3(Δex7/8) mice harbor the most common genetic defect causing juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive disease involving seizures, visual, motor and cognitive decline, and premature death. Here, to more thoroughly investigate the manifestations of the common JNCL mutation, we performed a broad phenotyping study of Cln3(Δex7/8) mice. Homozygous Cln3(Δex7/8) mice, congenic on a C57BL/6N background, displayed subtle deficits in sensory and motor tasks at 10-14 weeks of age. Homozygous Cln3(Δex7/8) mice also displayed electroretinographic changes reflecting cone function deficits past 5 months of age and a progressive decline of retinal post-receptoral function. Metabolic analysis revealed increases in rectal body temperature and minimum oxygen consumption in 12-13 week old homozygous Cln3(Δex7/8) mice, which were also seen to a lesser extent in heterozygous Cln3(Δex7/8) mice. Heart weight was slightly increased at 20 weeks of age, but no significant differences were observed in cardiac function in young adults. In a comprehensive blood analysis at 15-16 weeks of age, serum ferritin concentrations, mean corpuscular volume of red blood cells (MCV), and reticulocyte counts were reproducibly increased in homozygous Cln3(Δ) (ex7/8) mice, and male homozygotes had a relative T-cell deficiency, suggesting alterations in hematopoiesis. Finally, consistent with findings in JNCL patients, vacuolated peripheral blood lymphocytes were observed in homozygous Cln3(Δ) (ex7/8) neonates, and to a greater extent in older animals. Early onset, severe vacuolation in clear cells of the epididymis of male homozygous Cln3(Δ) (ex7/8) mice was also observed. These data highlight additional organ systems in which to study CLN3 function, and early phenotypes have been established in homozygous Cln3(Δ) (ex7/8) mice that merit further study for JNCL biomarker development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0038310PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3368842PMC
November 2012

Mice with an induced mutation in collagen 8A2 develop larger eyes and are resistant to retinal ganglion cell damage in an experimental glaucoma model.

Mol Vis 2012 1;18:1093-106. Epub 2012 May 1.

Glaucoma Center of Excellence, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, MD, USA.

Purpose: To study susceptibility to glaucoma injury as it may be affected by mutations in ocular connective tissue components.

Methods: Mice homozygous for an N-ethyl-N-nitrosourea induced G257D exchange (Gly to Asp) missense mutation (Aca23) in their collagen 8A2 gene were studied to measure intraocular pressure (IOP), axial length and width, number of retinal ganglion cells (RGC), and inflation responses. Three month old homozygous Aca23 mutant and wild type (WT) mice had 6 weeks exposure to elevated IOP induced by polystyrene microbead injection. Additional Aca23 and matched controls were studied at ages of 10 and 18 months.

Results: Aca23 mice had no significant difference from WT in IOP level, and in both strains IOP rose with age. In multivariable models, axial length and width were significantly larger in Aca23 than WT, became larger with age, and were larger after exposure to glaucoma (n=227 mice). From inflation test data, the estimates of scleral stress resultants in Aca23 mice were similar to age-matched and younger WT C57BL/6 (B6) mice, while the strain estimates for Aca23 were significantly less than those for either WT group in the mid-sclera and in some of the more anterior scleral measures (p<0.001; n=29, 22, 20 eyes in Aca23, older WT, younger WT, respectively). With chronic IOP elevation, Aca23 eyes increased 9% in length and 7% in width, compared to untreated fellow eyes (p<0.05, <0.01). With similar elevated IOP exposure, WT eyes enlarged proportionately twice as much as Aca23, increasing in length by 18% and in nasal-temporal width by 13% (both p<0.001, Mann-Whitney test). In 4 month old control optic nerves, mean RGC axon number was not different in Aca23 and WT (46,905±7,592, 43,628±11,162, respectively; p=0.43, Mann-Whitney test, n=37 and 29). With chronic glaucoma, Aca23 mice had a mean axon loss of only 0.57±17%, while WT mice lost 21±31% (median loss: 1% versus 10%, n=37, 29, respectively; p=0.001; multivariable model adjusting for positive integral IOP exposure).

Conclusions: The Aca23 mutation in collagen 8α2 is the first gene defect found to alter susceptibility to experimental glaucoma, reducing RGC loss possibly due to differences in mechanical behavior of the sclera. Detailed study of the specific changes in scleral connective tissue composition and responses to chronic IOP elevation in this strain could produce new therapeutic targets for RGC neuroprotection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374490PMC
November 2012

The pathologic effect of a novel neomorphic Fgf9(Y162C) allele is restricted to decreased vision and retarded lens growth.

PLoS One 2011 17;6(8):e23678. Epub 2011 Aug 17.

German Research Center for Environmental Health, Institute of Developmental Genetics, Neuherberg, Germany.

Fibroblast growth factor (Fgf) signalling plays a crucial role in many developmental processes. Among the Fgf pathway ligands, Fgf9 (UniProt: P54130) has been demonstrated to participate in maturation of various organs and tissues including skeleton, testes, lung, heart, and eye. Here we establish a novel Fgf9 allele, discovered in a dominant N-ethyl-N-nitrosourea (ENU) screen for eye-size abnormalities using the optical low coherence interferometry technique. The underlying mouse mutant line Aca12 was originally identified because of its significantly reduced lens thickness. Linkage studies located Aca12 to chromosome 14 within a 3.6 Mb spanning interval containing the positional candidate genes Fgf9 (MGI: 104723), Gja3 (MGI: 95714), and Ift88 (MGI: 98715). While no sequence differences were found in Gja3 and Ift88, we identified an A→G missense mutation at cDNA position 770 of the Fgf9 gene leading to an Y162C amino acid exchange. In contrast to previously described Fgf9 mutants, Fgf9(Y162C) carriers were fully viable and did not reveal reduced body-size, male-to-female sexual reversal or skeletal malformations. The histological analysis of the retina as well as its basic functional characterization by electroretinography (ERG) did not show any abnormality. However, the analysis of head-tracking response of the Fgf9(Y162C) mutants in a virtual drum indicated a gene-dosage dependent vision loss of almost 50%. The smaller lenses in Fgf9(Y162C) suggested a role of Fgf9 during lens development. Histological investigations showed that lens growth retardation starts during embryogenesis and continues after birth. Young Fgf9(Y162C) lenses remained transparent but developed age-related cataracts. Taken together, Fgf9(Y162C) is a novel neomorphic allele that initiates microphakia and reduced vision without effects on organs and tissues outside the eye. Our data point to a role of Fgf9 signalling in primary and secondary lens fiber cell growth. The results underline the importance of allelic series to fully understand multiple functions of a gene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0023678PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3157460PMC
February 2012

Microphakia and congenital cataract formation in a novel Lim2(C51R) mutant mouse.

Mol Vis 2011 4;17:1164-71. Epub 2011 May 4.

Helmholtz Center Munich, German Research Center for Environmental Health, Institutes of Developmental Genetics, Neuherberg, Germany.

Purpose: Within a mutagenesis screen, we identified the new mouse mutant Aca47 with small lenses and reduced axial eye lengths. The aim of the actual study was the molecular and morphological characterization of the mouse mutant Aca47.

Methods: We analyzed the offspring of paternally N-ethyl-N-nitrosourea (ENU) treated C57BL/6J mice for eye-size parameters by non-invasive in vivo laser interference biometry. Linkage analysis of the eye size mutant Aca47 was performed using single nucleotide polymorphisms and microsatellite markers. The Aca47 mutation was identified by sequence analysis of positional candidate genes. A general polymorphism at the mutated site was excluded by restriction analysis. Eyes of the Aca47 mouse mutant were characterized by histology. Visual properties were examined in the virtual drum.

Results: We identified a new mutant characterized by a significantly smaller lens and reduced axial eye length without any changes for cornea thickness, anterior chamber depth or aqueous humor size. The smaller size of lens was more pronounced in the homozygous mutants, which further developed congenital cataracts in the lens nucleus. The mutation was mapped to chromosome 7 between the markers D7Mit247 and D7Mit81. Using a positional candidate approach, the lens intrinsic integral membrane protein MP19 encoding gene Lim2 was sequenced; a T → C exchange at cDNA position 151 leads to a cysteine-to-arginine substitution at position 51 of the Lim2 protein. Eye histology of adult heterozygous mutants did not show alterations on the cellular level. However, homozygous lenses revealed irregularly arranged lens fiber layers in the cortex. Virtual vision tests indicated that visual properties are not affected by reduced eye size of heterozygous individuals.

Conclusions: These findings demonstrate a novel missense mutation in the Lim2 gene that affects lens development in a semidominant manner. Since homozygous mutants develop congenital lens opacities, this line can be used as a model for inherited cataract formation in humans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102026PMC
September 2011

Requirement of the RNA-editing enzyme ADAR2 for normal physiology in mice.

J Biol Chem 2011 May 5;286(21):18614-22. Epub 2011 Apr 5.

Institute of Experimental Genetics, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.

ADAR2, an RNA editing enzyme that converts specific adenosines to inosines in certain pre-mRNAs, often leading to amino acid substitutions in the encoded proteins, is mainly expressed in brain. Of all ADAR2-mediated edits, a single one in the pre-mRNA of the AMPA receptor subunit GluA2 is essential for survival. Hence, early postnatal death of mice lacking ADAR2 is averted when the critical edit is engineered into both GluA2 encoding Gria2 alleles. Adar2(-/-)/Gria2(R/R) mice display normal appearance and life span, but the general phenotypic effects of global lack of ADAR2 have remained unexplored. Here we have employed the Adar2(-/-)/Gria2(R/R) mouse line, and Gria2(R/R) mice as controls, to study the phenotypic consequences of loss of all ADAR2-mediated edits except the critical one in GluA2. Our extended phenotypic analysis covering ∼320 parameters identified significant changes related to absence of ADAR2 in behavior, hearing ability, allergy parameters and transcript profiles of brain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M110.200881DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3099677PMC
May 2011

First mutation in the βA2-crystallin encoding gene is associated with small lenses and age-related cataracts.

Invest Ophthalmol Vis Sci 2011 Apr 20;52(5):2571-6. Epub 2011 Apr 20.

Institutes of Developmental Genetics, Helmholtz Center Munich, German Research Center for Environmental Health, Ingolstädter Landstrasse 1, Neuherberg, Germany.

Purpose: A new mouse mutant with small lenses was identified within a mutagenesis screen. The aim of the study was to determine its molecular and morphologic characterization.

Methods: The offspring of paternally N-ethyl-N-nitrosourea (ENU)-treated C57BL/6J mice were analyzed for eye-size parameters by noninvasive in vivo laser interference biometry.

Results: A new mutant characterized by a clear, but significantly smaller lens without any changes for cornea thickness, anterior chamber depth, or aqueous humor size, was identified. The smaller size of the lens was more pronounced in the homozygous mutants, which were fully fertile and viable. The mutation was mapped to chromosome 1 between the markers D1Mit251 and D1Mit253. Using a positional candidate approach, the βA2-crystallin encoding gene Cryba2 was sequenced; a T→C exchange at cDNA position 139 led to a p.S47P amino-acid alteration. The eyes of newborn homozygous mutants showed no gross changes. At the age of three weeks, some clefts appeared at the cornea, but the lens and retina appeared without major changes. At the age of 25 weeks, the lenses of the heterozygous mutants develop a subcapsular cortical cataract, but the lenses of homozygous mutants were completely opaque.

Conclusions: These findings demonstrate the first mutation in the Cryba2 gene. In contrast to the closely linked Cryg gene cluster, no congenital cataract mutation could be attributed to the Cryba2 gene. Therefore, the human CRYBA2 gene should be considered as a strong candidate gene for age-related cataracts, and the slightly smaller size of the lens might be recognized as an early biomarker for age-related cataracts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1167/iovs.10-6443DOI Listing
April 2011