Publications by authors named "Glauco P Tocchini-Valentini"

44 Publications

Gpr37l1/prosaposin receptor regulates Ptch1 trafficking, Shh production, and cell proliferation in cerebellar primary astrocytes.

J Neurosci Res 2020 Dec 17. Epub 2020 Dec 17.

Institute of Biochemistry and Cell Biology, Italian National Research Council (CNR), Monterotondo Scalo, Rome, Italy.

Mammalian cerebellar astrocytes critically regulate the differentiation and maturation of neuronal Purkinje cells and granule precursors. The G protein-coupled receptor 37-like 1 (Gpr37l1) is expressed by Bergmann astrocytes and interacts with patched 1 (Ptch1) at peri-ciliary membranes. Cerebellar primary astrocyte cultures from wild-type and Gpr37l1 null mutant mouse pups were established and studied. Primary cilia were produced by cultures of both genotypes, as well as Ptch1 and smoothened (Smo) components of the sonic hedgehog (Shh) mitogenic pathway. Compared to wild-type cells, Gpr37l1 astrocytes displayed striking increases in proliferative activity, Ptch1 protein expression and internalization, intracellular cholesterol content, ciliary localization of Smo, as well as a marked production of active Shh. Similar effects were reproduced by treating wild-type astrocytes with a putative prosaptide ligand of Gpr37l1. These findings indicate that Gpr37l1-Ptch1 interactions specifically regulate Ptch1 internalization and trafficking, with consequent stimulation of Shh production and activation of proliferative signaling.
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http://dx.doi.org/10.1002/jnr.24775DOI Listing
December 2020

Soft windowing application to improve analysis of high-throughput phenotyping data.

Bioinformatics 2020 03;36(5):1492-1500

European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.

Motivation: High-throughput phenomic projects generate complex data from small treatment and large control groups that increase the power of the analyses but introduce variation over time. A method is needed to utlize a set of temporally local controls that maximizes analytic power while minimizing noise from unspecified environmental factors.

Results: Here we introduce 'soft windowing', a methodological approach that selects a window of time that includes the most appropriate controls for analysis. Using phenotype data from the International Mouse Phenotyping Consortium (IMPC), adaptive windows were applied such that control data collected proximally to mutants were assigned the maximal weight, while data collected earlier or later had less weight. We applied this method to IMPC data and compared the results with those obtained from a standard non-windowed approach. Validation was performed using a resampling approach in which we demonstrate a 10% reduction of false positives from 2.5 million analyses. We applied the method to our production analysis pipeline that establishes genotype-phenotype associations by comparing mutant versus control data. We report an increase of 30% in significant P-values, as well as linkage to 106 versus 99 disease models via phenotype overlap with the soft-windowed and non-windowed approaches, respectively, from a set of 2082 mutant mouse lines. Our method is generalizable and can benefit large-scale human phenomic projects such as the UK Biobank and the All of Us resources.

Availability And Implementation: The method is freely available in the R package SmoothWin, available on CRAN http://CRAN.R-project.org/package=SmoothWin.

Supplementary Information: Supplementary data are available at Bioinformatics online.
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http://dx.doi.org/10.1093/bioinformatics/btz744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115897PMC
March 2020

Functional loss of leads to hydrocephalus in a mouse model of primary ciliary dyskinesia.

Dis Model Mech 2019 08 2;12(8). Epub 2019 Aug 2.

European Mouse Mutant Archive (EMMA), INFRAFRONTIER, Monterotondo Mouse Clinic, Department of Biomedical Sciences (DSB), Italian National Research Council (CNR), Adriano Buzzati-Traverso Campus, via Ramarini, 32, 00015, Monterotondo, Rome, Italy.

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder affecting normal structure and function of motile cilia, phenotypically manifested as chronic respiratory infections, laterality defects and infertility. Autosomal recessive mutations in genes encoding for different components of the ciliary axoneme have been associated with PCD in humans and in model organisms. The gene encodes for a coiled-coil axonemal protein that ensures correct attachment of outer dynein arm (ODA) complexes to microtubules. A correct arrangement of dynein arm complexes is required to provide the proper mechanical force necessary for cilia beat. Loss-of-function mutations in in humans leads to PCD disease with respiratory distress and defective left-right body asymmetry. In mice with the loss-of-function mutation ( mutant), left-right body asymmetry with heart defects have been observed. Here, we demonstrate that loss of gene function via targeted gene deletion in mice leads to perinatal lethality and congenital hydrocephalus. Microcomputed tomography (microCT) X-ray imaging of Ccdc151-β-galactosidase reporter expression in whole-mount brain and histological analysis show that is expressed in ependymal cells lining the ventricular brain system, further confirming the role of dysfunction in hydrocephalus development. Analyzing the features of hydrocephalus in the -knockout animals by microCT volumetric imaging, we observe continuity of the aqueduct of Sylvius, indicating the communicating nature of hydrocephalus in the -knockout animals. Congenital defects in left-right asymmetry and male infertility have been also observed in null animals. gene deletion in adult animals results in abnormal sperm counts and defective sperm motility.This article has an associated First Person interview with the joint first authors of the paper.
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http://dx.doi.org/10.1242/dmm.038489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6737950PMC
August 2019

Genetic ablation of Gpr37l1 delays tumor occurrence in Ptch1 mouse models of medulloblastoma.

Exp Neurol 2019 02 16;312:33-42. Epub 2018 Nov 16.

Institute of Cell Biology and Neurobiology, Italian National Research Council (CNR), I-00015, Monterotondo Scalo, Rome, Italy.

The G-protein coupled receptor 37-like 1 (Gpr37l1) is specifically expressed in most astrocytic glial cells, including cerebellar Bergmann astrocytes and interacts with patched 1 (Ptch1), a co-receptor of the sonic hedgehog (Shh)-smoothened (Smo) signaling complex. Gpr37l1 null mutant mice exhibit precocious post-natal cerebellar development, with altered Shh-Smo mitogenic cascade and premature down-regulation of granule cell precursor (GCP) proliferation. Gpr37l1 expression is downregulated in medulloblastoma (MB) and upregulated in glioma and glioblastoma tumors. Shh-associated MBs originate postnatally, from dysregulated hyperproliferation of GCPs in developing cerebellum's external granular layer (EGL), as shown in heterozygous Ptch1 knock-out mouse strains that model human MB occurrence and progression. This study investigates cerebellar MB phenotypes in newly produced Gpr37l1, Ptch1 double mutant mice. Natural history analysis shows that Gpr37l1 genetic ablation, in Ptch1 model animals, results in marked deferment of post-natal tumor occurrence and decreased incidence of more aggressive tumor types. It is also associated with the delayed and diminished presence of more severe types of hyperplastic lesions in Ptch1 mice. Consistently, during early post-natal development Gpr37l1;Ptch1 pups exhibit reduction in cerebellar GCP proliferation and EGL thickness and a precocious, sustained expression of wingless-type MMTV integration site member 3 (Wnt3), a specific inhibitor of Shh-induced neuronal mitogenesis, in comparison with Ptch1 heterozygous single mutants. These findings highlight the specific involvement of Gpr37l1 in modulating postnatal cerebellar Shh-Ptch1-Smo mitogenic signaling in both normal and pathological conditions. The novel Gpr37l1;Ptch1 mouse models may thus be instrumental in the detailed characterization of the initial phases of Shh-associated MB insurgence and development.
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http://dx.doi.org/10.1016/j.expneurol.2018.11.004DOI Listing
February 2019

MicroRNA degradation by a conserved target RNA regulates animal behavior.

Nat Struct Mol Biol 2018 03 26;25(3):244-251. Epub 2018 Feb 26.

Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France.

microRNAs (miRNAs) repress target transcripts through partial complementarity. By contrast, highly complementary miRNA-binding sites within viral and artificially engineered transcripts induce miRNA degradation in vitro and in cell lines. Here, we show that a genome-encoded transcript harboring a near-perfect and deeply conserved miRNA-binding site for miR-29 controls zebrafish and mouse behavior. This transcript originated in basal vertebrates as a long noncoding RNA (lncRNA) and evolved to the protein-coding gene NREP in mammals, where the miR-29-binding site is located within the 3' UTR. We show that the near-perfect miRNA site selectively triggers miR-29b destabilization through 3' trimming and restricts its spatial expression in the cerebellum. Genetic disruption of the miR-29 site within mouse Nrep results in ectopic expression of cerebellar miR-29b and impaired coordination and motor learning. Thus, we demonstrate an endogenous target-RNA-directed miRNA degradation event and its requirement for animal behavior.
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http://dx.doi.org/10.1038/s41594-018-0032-xDOI Listing
March 2018

Identification of genetic elements in metabolism by high-throughput mouse phenotyping.

Nat Commun 2018 01 18;9(1):288. Epub 2018 Jan 18.

German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.

Metabolic diseases are a worldwide problem but the underlying genetic factors and their relevance to metabolic disease remain incompletely understood. Genome-wide research is needed to characterize so-far unannotated mammalian metabolic genes. Here, we generate and analyze metabolic phenotypic data of 2016 knockout mouse strains under the aegis of the International Mouse Phenotyping Consortium (IMPC) and find 974 gene knockouts with strong metabolic phenotypes. 429 of those had no previous link to metabolism and 51 genes remain functionally completely unannotated. We compared human orthologues of these uncharacterized genes in five GWAS consortia and indeed 23 candidate genes are associated with metabolic disease. We further identify common regulatory elements in promoters of candidate genes. As each regulatory element is composed of several transcription factor binding sites, our data reveal an extensive metabolic phenotype-associated network of co-regulated genes. Our systematic mouse phenotype analysis thus paves the way for full functional annotation of the genome.
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http://dx.doi.org/10.1038/s41467-017-01995-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5773596PMC
January 2018

Three-dimensional microCT imaging of murine embryonic development from immediate post-implantation to organogenesis: application for phenotyping analysis of early embryonic lethality in mutant animals.

Mamm Genome 2018 04 23;29(3-4):245-259. Epub 2017 Nov 23.

Institute of Cell Biology and Neurobiology (IBCN), via Ramarini, 32, 00015, Monterotondo, Rome, Italy.

In this work, we applied three-dimensional microCT imaging to study murine embryogenesis in the range from immediate post-implantation period (embryonic day 5.5) to mid-gestation (embryonic day 12.5) with the resolution up to 1.4 µm/voxel. Also, we introduce an imaging procedure for non-invasive volumetric estimation of an entire litter of embryos within the maternal uterine structures. This method allows for an accurate, detailed and systematic morphometric analysis of both embryonic and extra-embryonic components during embryogenesis. Three-dimensional imaging of unperturbed embryos was performed to visualize the egg cylinder, primitive streak, gastrulation and early organogenesis stages of murine development in the C57Bl6/N mouse reference strain. Further, we applied our microCT imaging protocol to determine the earliest point when embryonic development is arrested in a mouse line with knockout for tRNA splicing endonuclease subunit Tsen54 gene. Our analysis determined that the embryonic development in Tsen54 null embryos does not proceed beyond implantation. We demonstrated that application of microCT imaging to entire litter of non-perturbed embryos greatly facilitate studies to unravel gene function during early embryogenesis and to determine the precise point at which embryonic development is arrested in mutant animals. The described method is inexpensive, does not require lengthy embryos dissection and can be applicable for detailed analysis of mutant mice at laboratory scale as well as for high-throughput projects.
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http://dx.doi.org/10.1007/s00335-017-9723-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5887010PMC
April 2018

Corrigendum: High-throughput discovery of novel developmental phenotypes.

Nature 2017 11 8;551(7680):398. Epub 2017 Nov 8.

This corrects the article DOI: 10.1038/nature19356.
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http://dx.doi.org/10.1038/nature24643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5849394PMC
November 2017

A large scale hearing loss screen reveals an extensive unexplored genetic landscape for auditory dysfunction.

Nat Commun 2017 10 12;8(1):886. Epub 2017 Oct 12.

Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK.

The developmental and physiological complexity of the auditory system is likely reflected in the underlying set of genes involved in auditory function. In humans, over 150 non-syndromic loci have been identified, and there are more than 400 human genetic syndromes with a hearing loss component. Over 100 non-syndromic hearing loss genes have been identified in mouse and human, but we remain ignorant of the full extent of the genetic landscape involved in auditory dysfunction. As part of the International Mouse Phenotyping Consortium, we undertook a hearing loss screen in a cohort of 3006 mouse knockout strains. In total, we identify 67 candidate hearing loss genes. We detect known hearing loss genes, but the vast majority, 52, of the candidate genes were novel. Our analysis reveals a large and unexplored genetic landscape involved with auditory function.The full extent of the genetic basis for hearing impairment is unknown. Here, as part of the International Mouse Phenotyping Consortium, the authors perform a hearing loss screen in 3006 mouse knockout strains and identify 52 new candidate genes for genetic hearing loss.
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http://dx.doi.org/10.1038/s41467-017-00595-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5638796PMC
October 2017

Disease model discovery from 3,328 gene knockouts by The International Mouse Phenotyping Consortium.

Nat Genet 2017 Aug 26;49(8):1231-1238. Epub 2017 Jun 26.

William Harvey Research Institute, Queen Mary University of London, London, UK.

Although next-generation sequencing has revolutionized the ability to associate variants with human diseases, diagnostic rates and development of new therapies are still limited by a lack of knowledge of the functions and pathobiological mechanisms of most genes. To address this challenge, the International Mouse Phenotyping Consortium is creating a genome- and phenome-wide catalog of gene function by characterizing new knockout-mouse strains across diverse biological systems through a broad set of standardized phenotyping tests. All mice will be readily available to the biomedical community. Analyzing the first 3,328 genes identified models for 360 diseases, including the first models, to our knowledge, for type C Bernard-Soulier, Bardet-Biedl-5 and Gordon Holmes syndromes. 90% of our phenotype annotations were novel, providing functional evidence for 1,092 genes and candidates in genetically uncharacterized diseases including arrhythmogenic right ventricular dysplasia 3. Finally, we describe our role in variant functional validation with The 100,000 Genomes Project and others.
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http://dx.doi.org/10.1038/ng.3901DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5546242PMC
August 2017

High-throughput discovery of novel developmental phenotypes.

Nature 2016 09 14;537(7621):508-514. Epub 2016 Sep 14.

The Jackson Laboratory, Bar Harbor, Maine 04609, USA.

Approximately one-third of all mammalian genes are essential for life. Phenotypes resulting from knockouts of these genes in mice have provided tremendous insight into gene function and congenital disorders. As part of the International Mouse Phenotyping Consortium effort to generate and phenotypically characterize 5,000 knockout mouse lines, here we identify 410 lethal genes during the production of the first 1,751 unique gene knockouts. Using a standardized phenotyping platform that incorporates high-resolution 3D imaging, we identify phenotypes at multiple time points for previously uncharacterized genes and additional phenotypes for genes with previously reported mutant phenotypes. Unexpectedly, our analysis reveals that incomplete penetrance and variable expressivity are common even on a defined genetic background. In addition, we show that human disease genes are enriched for essential genes, thus providing a dataset that facilitates the prioritization and validation of mutations identified in clinical sequencing efforts.
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http://dx.doi.org/10.1038/nature19356DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5295821PMC
September 2016

Analysis of random PCR-originated mutants of the yeast Ste2 and Ste3 receptors.

Microbiologyopen 2016 08 5;5(4):670-86. Epub 2016 May 5.

CNR, Institute of Cell Biology and Neurobiology (IBCN), Monterotondo (Rome), 00015, Italy.

The G protein-coupled receptors Ste2 and Ste3 bind α- and a-factor, respectively, in Saccharomyces cerevisiae. These receptors share a similar conformation, with seven transmembrane segments, three intracellular loops, a C-terminus tail, and three extracellular loops. However, the amino acid sequences of these two receptors bear no resemblance to each other. Coincidently the two ligands, α- and a-factor, have different sequences. Both receptors activate the same G protein. To identify amino acid residues that are important for signal transduction, the STE2 and STE3 genes were mutagenized by a random PCR-based method. Mutant receptors were analyzed in MATα cells mutated in the ITC1 gene, whose product represses transcription of a-specific genes in MATα. Expression of STE2 or STE3 in these cells results in autocrine activation of the mating pathway, since this strain produces the Ste2 receptor in addition to its specific ligand, α-factor. It also produces a-factor in addition to its specific receptor, Ste3. Therefore, this strain provides a convenient model to analyze mutants of both receptors in the same background. Many hyperactive mutations were found in STE3, whereas none was detected in STE2. This result is consistent with the different strategies that the two genes have adopted to be expressed.
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http://dx.doi.org/10.1002/mbo3.361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985600PMC
August 2016

Primary Cilia in the Murine Cerebellum and in Mutant Models of Medulloblastoma.

Cell Mol Neurobiol 2017 Jan 2;37(1):145-154. Epub 2016 Mar 2.

Institute of Cell Biology and Neurobiology, Italian National Research Council (CNR), EMMA-INFRAFRONTIER-IMPC, 00015, Monterotondo Scalo, Rome, Italy.

Cellular primary cilia crucially sense and transduce extracellular physicochemical stimuli. Cilium-mediated developmental signaling is tissue and cell type specific. Primary cilia are required for cerebellar differentiation and sonic hedgehog (Shh)-dependent proliferation of neuronal granule precursors. The mammalian G-protein-coupled receptor 37-like 1 is specifically expressed in cerebellar Bergmann glia astrocytes and participates in regulating postnatal cerebellar granule neuron proliferation/differentiation and Bergmann glia and Purkinje neuron maturation. The mouse receptor protein interacts with the patched 1 component of the cilium-associated Shh receptor complex. Mice heterozygous for patched homolog 1 mutations, like heterozygous patched 1 humans, have a higher incidence of Shh subgroup medulloblastoma (MB) and other tumors. Cerebellar cells bearing primary cilia were identified during postnatal development and in adulthood in two mouse strains with altered Shh signaling: a G-protein-coupled receptor 37-like 1 null mutant and an MB-susceptible, heterozygous patched homolog 1 mutant. In addition to granule and Purkinje neurons, primary cilia were also expressed by Bergmann glia astrocytes in both wild-type and mutant animals, from birth to adulthood. Variations in ciliary number and length were related to the different levels of neuronal and glial cell proliferation and maturation, during postnatal cerebellar development. Primary cilia were also detected in pre-neoplastic MB lesions in heterozygous patched homolog 1 mutant mice and they could represent specific markers for the development and analysis of novel cerebellar oncogenic models.
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http://dx.doi.org/10.1007/s10571-016-0354-3DOI Listing
January 2017

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

Applying the ARRIVE Guidelines to an In Vivo Database.

PLoS Biol 2015 May 20;13(5):e1002151. Epub 2015 May 20.

Mammalian Genetics Unit, Medical Research Council, Harwell, United Kingdom.

The Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines were developed to address the lack of reproducibility in biomedical animal studies and improve the communication of research findings. While intended to guide the preparation of peer-reviewed manuscripts, the principles of transparent reporting are also fundamental for in vivo databases. Here, we describe the benefits and challenges of applying the guidelines for the International Mouse Phenotyping Consortium (IMPC), whose goal is to produce and phenotype 20,000 knockout mouse strains in a reproducible manner across ten research centres. In addition to ensuring the transparency and reproducibility of the IMPC, the solutions to the challenges of applying the ARRIVE guidelines in the context of IMPC will provide a resource to help guide similar initiatives in the future.
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http://dx.doi.org/10.1371/journal.pbio.1002151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4439173PMC
May 2015

Modulation of Dhh signaling and altered Sertoli cell function in mice lacking the GPR37-prosaposin receptor.

FASEB J 2015 May 21;29(5):2059-69. Epub 2015 Jan 21.

Consiglio Nazionale delle Ricerche, Emma-Infrafrontier-Impc, "A. Buzzati-Traverso" Campus, Istituto di Biologia Cellulare e Neurobiologia, Monterotondo Scalo, Rome, Italy

The mammalian G-protein-coupled receptor 37 (GPR37) is expressed in brain, in adult testis, and during the early phase of gonad differentiation. Somatic Sertoli cells (SCs) are located within the seminiferous tubules where they support the germinal epithelium. An adequate number of SCs is required for the complete prepubertal differentiation of germ cells and adult fertility. This study shows that Gpr37 and its ligand prosaposin are both postnatally expressed by SCs, whose proliferation and maturation are affected in Gpr37-null mutant mice during postnatal testicular development. Mutant pups show a delayed timing in sperm cell development, with a partial arrest of spermatocytes at the meiotic pachytene (e.g., 1.5-fold increase in Gpr37(-/-) P21 pups) and their increased apoptosis (e.g., 1.8-fold and 3.5-fold increase in Gpr37(-/-) P21 and adult mice, respectively). Mutant adults have reduced testis weight (wild type, 299 ± 5 mg; knockout, 258 ± 16 mg; P < 0.05) and epididymal sperm count and motility (e.g., 1.5-fold and 1.45-fold decrease in Gpr37(-/-) mice, respectively). Lack of Gpr37 results in the reduction in androgen receptor levels during prepubertal testis development, alongside the altered expression of SC maturation markers. It also affects the prepubertal testis expression of desert hedgehog (Dhh) mitogenic cascade components (Dhh, 1.3-fold increase in Gpr37(-/-) P10 and P21 pups; Gli2, 1.4-fold and 1.6-fold increase in Gpr37(-/-) P10 and P21 pups, respectively) including patched homolog 1 (1.3-fold increase in Gpr37(-/-) P10 and P21 pups), which is found localized in prepubertal SCs and is associated with Gpr37 in cultured primary SC samples. These results indicate that Gpr37 is a specific modulator of murine testis Dhh mitogenic signaling and SC proliferation and maturation.
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http://dx.doi.org/10.1096/fj.14-269209DOI Listing
May 2015

Early motor deficits in mouse disease models are reliably uncovered using an automated home-cage wheel-running system: a cross-laboratory validation.

Dis Model Mech 2014 Mar 13;7(3):397-407. Epub 2014 Jan 13.

CNR - Institute of Cell Biology and Neurobiology - EMMA, 00015 Monterotondo Scalo, Italy.

Deficits in motor function are debilitating features in disorders affecting neurological, neuromuscular and musculoskeletal systems. Although these disorders can vary greatly with respect to age of onset, symptomatic presentation, rate of progression and severity, the study of these disease models in mice is confined to the use of a small number of tests, most commonly the rotarod test. To expand the repertoire of meaningful motor function tests in mice, we tested, optimised and validated an automated home-cage-based running-wheel system, incorporating a conventional wheel with evenly spaced rungs and a complex wheel with particular rungs absent. The system enables automated assessment of motor function without handler interference, which is desirable in longitudinal studies involving continuous monitoring of motor performance. In baseline studies at two test centres, consistently significant differences in performance on both wheels were detectable among four commonly used inbred strains. As further validation, we studied performance in mutant models of progressive neurodegenerative diseases--Huntington's disease [TgN(HD82Gln)81Dbo; referred to as HD mice] and amyotrophic lateral sclerosis [Tg(SOD1G93A)(dl)1/GurJ; referred to as SOD1 mice]--and in a mutant strain with subtle gait abnormalities, C-Snap25(Bdr)/H (Blind-drunk, Bdr). In both models of progressive disease, as with the third mutant, we could reliably and consistently detect specific motor function deficits at ages far earlier than any previously recorded symptoms in vivo: 7-8 weeks for the HD mice and 12 weeks for the SOD1 mice. We also conducted longitudinal analysis of rotarod and grip strength performance, for which deficits were still not detectable at 12 weeks and 23 weeks, respectively. Several new parameters of motor behaviour were uncovered using principal component analysis, indicating that the wheel-running assay could record features of motor function that are independent of rotarod performance. This represents a powerful new method to detect motor deficits at pre-symptomatic stages in mouse disease models and should be considered as a valid tool to investigate the efficacy of therapeutic agents.
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http://dx.doi.org/10.1242/dmm.013946DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3944499PMC
March 2014

Precocious cerebellum development and improved motor functions in mice lacking the astrocyte cilium-, patched 1-associated Gpr37l1 receptor.

Proc Natl Acad Sci U S A 2013 Oct 23;110(41):16486-91. Epub 2013 Sep 23.

Consiglio Nazionale delle Ricerche, European Mouse Mutant Archive-Infrafrontier-International Mouse Phenotyping Consortium, Istituto di Biologia Cellulare e Neurobiologia, I-00015 Monterotondo Scalo (Rome), Italy.

In the developing cerebellum, the proliferation and differentiation of glial and neuronal cell types depend on the modulation of the sonic hedgehog (Shh) signaling pathway. The vertebrate G-protein-coupled receptor 37-like 1 (GPR37L1) gene encodes a putative G-protein-coupled receptor that is expressed in newborn and adult cerebellar Bergmann glia astrocytes. This study shows that the ablation of the murine Gpr37l1 gene results in premature down-regulation of proliferation of granule neuron precursors and precocious maturation of Bergmann glia and Purkinje neurons. These alterations are accompanied by improved adult motor learning and coordination. Gpr37l1(-/-) mice also exhibit specific modifications of the Shh signaling cascade. Specific assays show that in Bergmann glia cells Gpr37l1 is associated with primary cilium membranes and it specifically interacts and colocalizes with the Shh primary receptor, patched 1. These findings indicate that the patched 1-associated Gpr37l1 receptor participates in the regulation of postnatal cerebellum development by modulating the Shh pathway.
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http://dx.doi.org/10.1073/pnas.1314819110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3799331PMC
October 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.
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http://dx.doi.org/10.1186/gb-2013-14-7-r82DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053787PMC
July 2013

Highly efficient, in vivo optimized, archaeal endonuclease for controlled RNA splicing in mammalian cells.

FASEB J 2013 Sep 16;27(9):3466-77. Epub 2013 May 16.

Consiglio Nazionale delle Ricerche, Istituto di Biologia Cellulare e Neurobiologia, European Mouse Mutant Archive, Monterotondo, Italy.

ARCHAEA-ExPRESs is an mRNA modification technology that makes use of components derived from the Archaeon Methanocaldococcus jannaschii, namely the tRNA splicing endonuclease (MJ-EndA) and its natural substrate, the bulge-helix-bulge (BHB) structure (1). These components can perform both cis- and trans-splicing in cellular and animal models and may provide a convenient way to modulate gene expression using components independent of cellular regulatory networks. To use MJ-EndA in stable expression mammalian systems, we developed variants characterized by high efficiency and sustainable in vivo activity. The MJ-EndA variants were created by the introduction of proper localization signals followed by mutagenesis and direct selection in mammalian cells. Of note, enzyme selection used an in vivo selection method based on puromycin resistance conferred to cells by BHB-mediated intron splicing from an out-of-frame puromycin N-acetyl transferase (PAC) gene. This approach yielded several endonuclease variants, the best of which showed 40-fold higher activity compared to the parental enzyme and stable processing of 30% of the target mRNA. Notably, these variants showed complete compatibility with long-term expression in mammalian cells, suggesting that they may be usefully applied in functional genomics and genetically modified animal models.
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http://dx.doi.org/10.1096/fj.13-231993DOI Listing
September 2013

Avatar pre-tRNAs help elucidate the properties of tRNA-splicing endonucleases that produce tRNA from permuted genes.

Proc Natl Acad Sci U S A 2012 Dec 11;109(52):21325-9. Epub 2012 Dec 11.

Consiglio Nazionale delle Ricerche, Istituto di Biologia Cellulare e di Neurobiologia, European Mouse Mutant Archive, Monterotondo 00015, Italy.

Unusual tRNA genes, found in some algae, have their mature terminal 3' portion in front of their 5' portion in the genome. The transcripts from such genes must be cleaved by a pre-tRNA endonuclease to form a functional tRNA. We present a mechanism for the generation of "corrected" tRNAs from such a "permuted" pre-tRNA configuration. We used two avatar (av) or model pre-tRNAs and two splicing endonucleases with distinct mechanisms of recognition of the pre-tRNA. The splicing results are compatible with an evolutionary route in which permuted genes result from a duplication event followed by DNA rearrangement. The model pre-tRNAs permit description of the features that a transcript, derived from a rearranged duplicated gene, must have to give rise to functional tRNA. The two tRNA endonucleases are a eukaryal enzyme that normally acts in a mature domain-dependent mode and an archaeal enzyme that acts in a mature domain-independent mode. Both av pre-tRNAs are able to fold into two conformations: 1 and 2. We find that only conformation 2 can yield a corrected functional tRNA. This result is consistent with contemporary algae representing snapshots of different evolutionary stages, with duplicated genes preceding recombinatorial events generating a permutated gene. In a scenario elucidated by the use of the av pre-tRNAs, algal permuted tRNA genes could have further lost one of two mature domains, eliminating steric problems for the algal tRNA endonuclease, which remains a typical eukaryal enzyme capable of correcting the permuted transcript to a functional tRNA.
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http://dx.doi.org/10.1073/pnas.1219336110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3535657PMC
December 2012

The mammalian gene function resource: the International Knockout Mouse Consortium.

Mamm Genome 2012 Oct 12;23(9-10):580-6. Epub 2012 Sep 12.

The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1HH, UK.

In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed high-throughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research.
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http://dx.doi.org/10.1007/s00335-012-9422-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463800PMC
October 2012

Comparative anatomy: Giorgione's Venus, Connoisseur Morelli, and the Reverend Bayes.

FASEB J 2012 Jan;26(1):5-8

Consiglio Nazionale delle Ricerche, Rome, Italy.

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http://dx.doi.org/10.1096/fj.12-0102ufmDOI Listing
January 2012

Yeast pheromone receptor genes STE2 and STE3 are differently regulated at the transcription and polyadenylation level.

Proc Natl Acad Sci U S A 2011 Oct 3;108(41):17082-6. Epub 2011 Oct 3.

Cell Biology and Neurobiology Institute, Consiglio Nazionale delle Ricerche, Campus A. Buzzati-Traverso, 00015 Monterotondo, Rome, Italy.

The orderly expression of specific genes is the basis for cell differentiation. Saccharomyces cerevisiae has two haploid mating types, a and α cells, in which the mating-specific genes are differentially expressed. When a and α cells are committed to mate, their growth is arrested. Here we show that a cryptic polyadenylation site is present inside the coding region of the a-specific STE2 gene, encoding the receptor for the α-factor. The two cell types produce an incomplete STE2 transcript, but only a cells generate full-length STE2 mRNA. We eliminated the cryptic poly(A) signal, thereby allowing the production of a complete STE2 mRNA in α cells. We mutagenized α cells and isolated a mutant producing full-length STE2 mRNA. The mutation occurred in the ITC1 gene, whose product, together with the product of ISW2, is known to repress STE2 transcriptional initiation. We propose that the regulation of the yeast mating genes is achieved through a concerted mechanism involving transcriptional and posttranscriptional events. In particular, the early poly(A) site in STE2 could contribute to a complete shutoff of its expression in α cells, avoiding autocrine activation and growth arrest. Remarkably, no cryptic poly(A) sites are present in the a-factor receptor STE3 gene, indicating that S. cerevisiae has devised different strategies to regulate the two receptor genes. It is predictable that a correlation between the repression of a gene and the presence of a cryptic poly(A) site could also be found in other organisms, especially when expression of that gene may be harmful.
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http://dx.doi.org/10.1073/pnas.1114648108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3193217PMC
October 2011

Evolution of introns in the archaeal world.

Proc Natl Acad Sci U S A 2011 Mar 7;108(12):4782-7. Epub 2011 Mar 7.

Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A, Buzzati-Traverso, Via Ramarini 32, Monterotondo Scalo, 00016 Rome, Italy.

The self-splicing group I introns are removed by an autocatalytic mechanism that involves a series of transesterification reactions. They require RNA binding proteins to act as chaperones to correctly fold the RNA into an active intermediate structure in vivo. Pre-tRNA introns in Bacteria and in higher eukaryote plastids are typical examples of self-splicing group I introns. By contrast, two striking features characterize RNA splicing in the archaeal world. First, self-splicing group I introns cannot be found, to this date, in that kingdom. Second, the RNA splicing scenario in Archaea is uniform: All introns, whether in pre-tRNA or elsewhere, are removed by tRNA splicing endonucleases. We suggest that in Archaea, the protein recruited for splicing is the preexisting tRNA splicing endonuclease and that this enzyme, together with the ligase, takes over the task of intron removal in a more efficient fashion than the ribozyme. The extinction of group I introns in Archaea would then be a consequence of recruitment of the tRNA splicing endonuclease. We deal here with comparative genome analysis, focusing specifically on the integration of introns into genes coding for 23S rRNA molecules, and how this newly acquired intron has to be removed to regenerate a functional RNA molecule. We show that all known oligomeric structures of the endonuclease can recognize and cleave a ribosomal intron, even when the endonuclease derives from a strain lacking rRNA introns. The persistence of group I introns in mitochondria and chloroplasts would be explained by the inaccessibility of these introns to the endonuclease.
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http://dx.doi.org/10.1073/pnas.1100862108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3064391PMC
March 2011

Absence of the GPR37/PAEL receptor impairs striatal Akt and ERK2 phosphorylation, DeltaFosB expression, and conditioned place preference to amphetamine and cocaine.

FASEB J 2011 Jun 3;25(6):2071-81. Epub 2011 Mar 3.

Istituto di Biologia Cellulare-Consiglio Nazionale delle Ricerche, Campus A. Buzzati-Traverso, Via E. Ramarini 32, I-00015 Monterotondo Scalo, Rome, Italy.

The orphan G-protein-coupled receptor 37 (GPR37) colocalizes with the dopamine (DA) transporter (DAT) in mouse nigrostriatal presynaptic membranes, and its genetic ablation in homozygous null-mutant (GPR37-KO) mice provokes the marked increase of plasma membrane expression of DAT, alteration of psychostimulant-induced locomotor activity, and reduction of catalepsy induced by DA-receptor antagonists. We report that extracts from GPR37-KO mice displayed biochemical alterations of the nigrostriatal signaling pathways mediated by D1 and D2 dopaminergic receptors. Null-mutant mice showed an increase of the basal phosphorylation level of the D2-regulated Akt kinase. The basal phosphorylation of the D1-activated ERK2 kinase was not altered, but acute treatments with amphetamine or cocaine failed to produce its specific increase, as detected in samples from wild-type littermates. Furthermore, the chronic administration of cocaine to GPR37-KO mice did not increase the expression of the ΔFosB transcription factor isoforms. Consistently, behavioral analysis showed that null-mutant animals did not respond to the incentive properties of amphetamine or cocaine, in conditioned place preference tests. Thus, the lack of GPR37 affects both ERK2- and Akt-mediated striatal signaling pathways, impairing the biochemical and behavioral responses typically induced by acute and chronic administration of psychostimulant drugs.
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http://dx.doi.org/10.1096/fj.10-175737DOI Listing
June 2011

ARCHAEA-ExPRESs targeting of alpha-tubulin 4 mRNA: a model for high-specificity trans-splicing.

FASEB J 2010 Aug 6;24(8):2976-84. Epub 2010 Apr 6.

Istituto di Biologia Cellulare-CNR, Campus A. Buzzati-Traverso, Via E. Ramarini 32, I-00015 Monterondo Scalo, Rome, Italy.

Effectiveness of trans-splicing-mediated mRNA reprogramming depends on specificity and efficiency. We have previously developed a new strategy (ARCHAEA-ExPRESs) that uses a tRNA endonuclease derived from Archaea and its natural substrate, the bulge-helix-bulge (BHB) structure. ARCHAEA-ExPRESs provides increased specificity in functional targeting. In fact, this system is based on a double check, the base pairing and the formation of a BHB structure between the target mRNA and the targeting RNA. In this study, we demonstrate the high specificity of ARCHAEA-ExPRESs by tagging the endogenous alpha-tubulin 4 via trans-splicing. Alpha-tubulin 4 belongs to a gene family sharing high degree of nucleotide sequence homology. The formation of a perfect BHB structure between targeting RNAs and the isotype alpha-tubulin 4 enables selective trans-splicing. Most important, ARCHAEA-ExPRESs functionality is conserved in vivo following transient expression of archaeal tRNA endonuclease in mouse liver. Production of the recombinant protein is strictly dependent on the expression of the archaeal endonuclease, and the efficiency of the system depends on the relative amount of the target and targeting mRNAs. These data prove the effectiveness of ARCHAEA-ExPRESs in an endogenous highly demanding context and disclose the possibility to utilize this system in a variety of technological or therapeutic applications.
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http://dx.doi.org/10.1096/fj.10-154658DOI Listing
August 2010

Processing of multiple-intron-containing pretRNA.

Proc Natl Acad Sci U S A 2009 Dec 12;106(48):20246-51. Epub 2009 Nov 12.

Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A, Buzzati-Traverso, Via Ramarini 32, Monterotondo Scalo, 00016 Rome, Italy.

Computational studies predict the simultaneous presence of two and even three introns in certain crenarchaeal tRNA genes. In these multiple-intron-containing pretRNAs, the introns are nested one inside the other and the pretRNA folds into a conformation that is anticipated to allow splicing of the last intron only after splicing the others. A set of operations, each consisting of two cleavages and one ligation, therefore needs to be carried out sequentially. PretRNAs containing multiple introns are predicted to fold, forming bulge-helix-bulge (BHB) and BHB-like motifs. The tRNA splicing endonuclease should recognize these motifs. To test this hypothetical scenario, we used the homotetrameric enzyme from Methanocaldococcus jannaschii (METJA) and the heterotetrameric enzyme from Sulfolobus solfataricus (SULSO). On the basis of our previous studies, the METJA enzyme should cleave only the BHB structure motif, while the SULSO enzyme can in addition cleave variant substrate structures, like the bulge-helix-loop (BHL). We show here that the processing of multiple-intron-containing pretRNA can be observed in vitro.
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http://dx.doi.org/10.1073/pnas.0911658106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2787110PMC
December 2009

Splicing of mRNA mediated by tRNA sequences in mouse cells.

RNA 2009 Dec 22;15(12):2122-8. Epub 2009 Oct 22.

Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, 00015 Monterotondo, Rome, Italy.

tRNA splicing is essential for the formation of tRNAs and therefore for gene expression. A circularly permuted sequence of an amber-suppressor pre-tRNA gene was inserted into the sequence encoding the mouse NEMO protein. We demonstrated that, in mouse cells, the hybrid pre-tRNA/pre-mRNAs can be spliced precisely at the sites of the pre-tRNA intron. This splicing reaction produces functional tRNAs that suppress amber codons as well as translatable mRNAs that sustain the NF-kappaB activation pathway. The RNA molecules extracted from mouse cells were amplified by RT-PCR, and their sequences were determined, confirming the identity of the splice junctions. We then applied the Archaea-express technology, in which an archaeal RNA endonuclease is expressed in mouse cells. We show that both the endogenous eukaryal endonuclease and the archaeal one cleave the hybrid pre-tRNA/pre-mRNAs in the same manner with an additive effect.
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http://dx.doi.org/10.1261/rna.1841609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2779668PMC
December 2009

How to build a kangaroo the way a kangaroo builds itself.

FASEB J 2009 Oct;23(10):3257-9

Istituto di Biologia Cellulare, CNR, 1-00015 Monterotondo Scalo, Rome, Italy.

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http://dx.doi.org/10.1096/fj.09-1002DOI Listing
October 2009