Publications by authors named "Catherine M Owczarek"

17 Publications

  • Page 1 of 1

Targeting the human β receptor inhibits contact dermatitis in a transgenic mouse model.

J Invest Dermatol 2021 Sep 16. Epub 2021 Sep 16.

Centre for Cancer Biology, SA Pathology and the University of South Australia, Adelaide, South Australia, Australia.

Allergic contact dermatitis (ACD) is a prevalent and poorly controlled inflammatory disease caused by skin infiltration of T cells and granulocytes. The β cytokines GM-CSF, IL-3 and IL-5 are powerful regulators of granulocyte function that signal through their common receptor subunit β, a property that has made β an attractive target to simultaneously inhibit these cytokines. However, the species specificity of β has precluded testing of inhibitors of human β in mouse models. To overcome this problem, we developed a human β receptor transgenic (hβTg) mouse strain with hematopoietic cell-specific expression of human β instead of mouse β. hβTg cells responded to mouse GM-CSF and IL-5 but not IL-3 in vitro and developed tissue pathology and cellular inflammation comparable to wild-type mice in a model of ACD. Similarly, IL-3 mice developed ACD pathology comparable to wild-type mice. Importantly, the blocking anti-human β antibody CSL311 strongly suppressed ear pinna thickening and histopathological changes typical of ACD and reduced accumulation of neutrophils, mast cells and eosinophils in the skin. These results show that GM-CSF and IL-5, but not IL-3 are major mediators of ACD and define the hβTg mouse as a unique platform to test inhibitors of βin vivo.
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http://dx.doi.org/10.1016/j.jid.2021.07.183DOI Listing
September 2021

Modular Platform for the Development of Recombinant Hemoglobin Scavenger Biotherapeutics.

Mol Pharm 2021 08 22;18(8):3158-3170. Epub 2021 Jul 22.

Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich 8091, Switzerland.

Cell-free hemoglobin (Hb) is a driver of disease progression in conditions with intravascular or localized hemolysis. Genetic and acquired anemias or emergency medical conditions such as aneurysmal subarachnoid hemorrhage involve tissue Hb exposure. Haptoglobin (Hp) captures Hb in an irreversible protein complex and prevents its pathophysiological contributions to vascular nitric oxide depletion and tissue oxidation. Preclinical proof-of-concept studies suggest that human plasma-derived Hp is a promising therapeutic candidate for several Hb-driven diseases. Optimizing the efficacy and safety of Hb-targeting biotherapeutics may require structural and functional modifications for specific indications. Improved Hp variants could be designed to achieve the desired tissue distribution, metabolism, and elimination to target hemolytic disease states effectively. However, it is critical to ensure that these modifications maintain the function of Hp. Using transient mammalian gene expression of Hp combined with co-transfection of the pro-haptoglobin processing protease C1r-LP, we established a platform for generating recombinant Hp-variants. We designed an Hpβ-scaffold, which was expressed in this system at high levels as a monomeric unit (mini-Hp) while maintaining the key protective functions of Hp. We then used this Hpβ-scaffold as the basis to develop an initial proof-of-concept Hp fusion protein using human serum albumin as the fusion partner. Next, a hemopexin-Hp fusion protein with bispecific heme and Hb detoxification capacity was generated. Further, we developed a Hb scavenger devoid of CD163 scavenger receptor binding. The functions of these proteins were then characterized for Hb and heme-binding, binding of the Hp-Hb complexes with the clearance receptor CD163, antioxidant properties, and vascular nitric oxide sparing capacity. Our platform is designed to support the generation of innovative Hb scavenger biotherapeutics with novel modes of action and potentially improved formulation characteristics, function, and pharmacokinetics.
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http://dx.doi.org/10.1021/acs.molpharmaceut.1c00433DOI Listing
August 2021

Glycoproteomic measurement of site-specific polysialylation.

Anal Biochem 2020 05 20;596:113625. Epub 2020 Feb 20.

ARC Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD, 4072, Australia; School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, 4072, Australia. Electronic address:

Polysialylation is the enzymatic addition of a highly negatively charged sialic acid polymer to the non-reducing termini of glycans. Polysialylation plays an important role in development, and is involved in neurological diseases, neural tissue regeneration, and cancer. Polysialic acid (PSA) is also a biodegradable and non-immunogenic conjugate to therapeutic drugs to improve their pharmacokinetics. PSA chains vary in length, composition, and linkages, while the specific sites of polysialylation are important determinants of protein function. However, PSA is difficult to analyse by mass spectrometry (MS) due to its high negative charge and size. Most analytical approaches for analysis of PSA measure its degree of polymerization and monosaccharide composition, but do not address the key questions of site specificity and occupancy. Here, we developed a high-throughput LC-ESI-MS/MS glycoproteomics method to measure site-specific polysialylation of glycoproteins. This method measures site-specific PSA modification by using mild acid hydrolysis to eliminate PSA and sialic acids while leaving the glycan backbone intact, together with protease digestion followed by LC-ESI-MS/MS glycopeptide detection. PSA-modified glycopeptides are not detectable by LC-ESI-MS/MS, but become detectable after desialylation, allowing measurement of site-specific PSA occupancy. This method is an efficient analytical workflow for the study of glycoprotein polysialylation in biological and therapeutic settings.
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http://dx.doi.org/10.1016/j.ab.2020.113625DOI Listing
May 2020

Mining the Plasma Cell Transcriptome for Novel Cell Surface Proteins.

Int J Mol Sci 2018 Jul 24;19(8). Epub 2018 Jul 24.

The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia.

Antibody Secreting Cells (ASCs) are a fundamental component of humoral immunity, however, deregulated or excessive antibody production contributes to the pathology of autoimmune diseases, while transformation of ASCs results in the malignancy Multiple Myeloma (MM). Despite substantial recent improvements in treating these conditions, there is as yet no widely used ASC-specific therapeutic approach, highlighting a critical need to identify novel methods of targeting normal and malignant ASCs. Surface molecules specifically expressed by the target cell population represent ideal candidates for a monoclonal antibody-based therapy. By interrogating the ASC gene signature that we previously defined we identified three surface proteins, Plpp5, Clptm1l and Itm2c, which represent potential targets for novel MM treatments. , and are highly and selectively expressed by mouse and human ASCs as well as MM cells. To investigate the function of these proteins within the humoral immune system we have generated three novel mouse strains, each carrying a loss-of-function mutation in either , or . Through analysis of these novel strains, we have shown that Plpp5, Clptm1l and Itm2c are dispensable for the development, maturation and differentiation of B-lymphocytes, and for the production of antibodies by ASCs. As adult mice lacking either protein showed no apparent disease phenotypes, it is likely that targeting these molecules on ASCs will have minimal on-target adverse effects.
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http://dx.doi.org/10.3390/ijms19082161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121261PMC
July 2018

Role of the β Common (βc) Family of Cytokines in Health and Disease.

Cold Spring Harb Perspect Biol 2018 06 1;10(6). Epub 2018 Jun 1.

The Centre for Cancer Biology, SA Pathology and the University of South Australia, Adelaide, South Australia 5000, Australia.

The β common ([βc]/CD131) family of cytokines comprises granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-3, and IL-5, all of which use βc as their key signaling receptor subunit. This is a prototypic signaling subunit-sharing cytokine family that has unveiled many biological paradigms and structural principles applicable to the IL-2, IL-4, and IL-6 receptor families, all of which also share one or more signaling subunits. Originally identified for their functions in the hematopoietic system, the βc cytokines are now known to be truly pleiotropic, impacting on multiple cell types, organs, and biological systems, and thereby controlling the balance between health and disease. This review will focus on the emerging biological roles for the βc cytokines, our progress toward understanding the mechanisms of receptor assembly and signaling, and the application of this knowledge to develop exciting new therapeutic approaches against human disease.
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http://dx.doi.org/10.1101/cshperspect.a028514DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5983187PMC
June 2018

An Optimized Hepatitis C Virus E2 Glycoprotein Core Adopts a Functional Homodimer That Efficiently Blocks Virus Entry.

J Virol 2017 03 14;91(5). Epub 2017 Feb 14.

Centre for Biomedical Research, Burnet Institute, Melbourne, Australia

The hepatitis C virus (HCV) envelope glycoprotein E2 is the major target of broadly neutralizing antibodies and is the focus of efforts in the rational design of a universal B cell vaccine against HCV. The E2 glycoprotein exhibits a high degree of amino acid variability which localizes to three discrete regions: hypervariable region 1 (HVR1), hypervariable region 2 (HVR2), and the intergenotypic variable region (igVR). All three variable regions contribute to immune evasion and/or isolate-specific structural variations, both important considerations for vaccine design. A high-resolution structural definition of the intact HCV envelope glycoprotein complex containing E1 and E2 remains to be elucidated, while crystallographic structures of a recombinant E2 ectodomain failed to resolve HVR1, HVR2, and a major neutralization determinant adjacent to HVR1. To obtain further information on E2, we characterized the role of all three variable regions in E2 ectodomain folding and function in the context of a recombinant ectodomain fragment (rE2). We report that removal of the variable regions accelerates binding to the major host cell receptor CD81 and that simultaneous deletion of HVR2 and the igVR is required to maintain wild-type CD81-binding characteristics. The removal of the variable regions also rescued the ability of rE2 to form a functional homodimer. We propose that the rE2 core provides novel insights into the role of the variable motifs in the higher-order assembly of the E2 ectodomain and may have implications for E1E2 structure on the virion surface. Hepatitis C virus (HCV) infection affects ∼2% of the population globally, and no vaccine is available. HCV is a highly variable virus, and understanding the presentation of key antigenic sites at the virion surface is important for the design of a universal vaccine. This study investigates the role of three surface-exposed variable regions in E2 glycoprotein folding and function in the context of a recombinant soluble ectodomain. Our data demonstrate the variable motifs modulate binding of the E2 ectodomain to the major host cell receptor CD81 and have an impact on the formation of an E2 homodimer with high-affinity binding to CD81.
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http://dx.doi.org/10.1128/JVI.01668-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5309951PMC
March 2017

CSL311, a novel, potent, therapeutic monoclonal antibody for the treatment of diseases mediated by the common β chain of the IL-3, GM-CSF and IL-5 receptors.

MAbs 2016 14;8(3):436-53. Epub 2015 Dec 14.

a Research and Development, CSL Limited; Bio21 Molecular Science and Biotechnology Institute , Parkville Victoria , 3010 , Australia.

The β common-signaling cytokines interleukin (IL)-3, granulocyte-macrophage colony stimulating factor (GM-CSF) and IL-5 stimulate pro-inflammatory activities of haematopoietic cells via a receptor complex incorporating cytokine-specific α and shared β common (βc, CD131) receptor. Evidence from animal models and recent clinical trials demonstrate that these cytokines are critical mediators of the pathogenesis of inflammatory airway disease such as asthma. However, no therapeutic agents, other than steroids, that specifically and effectively target inflammation mediated by all 3 of these cytokines exist. We employed phage display technology to identify and optimize a novel, human monoclonal antibody (CSL311) that binds to a unique epitope that is specific to the cytokine-binding site of the human βc receptor. The binding epitope of CSL311 on the βc receptor was defined by X-ray crystallography and site-directed mutagenesis. CSL311 has picomolar binding affinity for the human βc receptor, and at therapeutic concentrations is a highly potent antagonist of the combined activities of IL-3, GM-CSF and IL-5 on primary eosinophil survival in vitro. Importantly, CSL311 inhibited the survival of inflammatory cells present in induced sputum from human allergic asthmatic subjects undergoing allergen bronchoprovocation. Due to its high potency and ability to simultaneously suppress the activity of all 3 β common cytokines, CSL311 may provide a new strategy for the treatment of chronic inflammatory diseases where the human βc receptor is central to pathogenesis. The coordinates for the βc/CSL311 Fab complex structure have been deposited with the RCSB Protein Data Bank (PDB 5DWU).
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http://dx.doi.org/10.1080/19420862.2015.1119352DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966837PMC
December 2016

Dual mechanism of interleukin-3 receptor blockade by an anti-cancer antibody.

Cell Rep 2014 Jul 17;8(2):410-9. Epub 2014 Jul 17.

The Centre for Cancer Biology, SA Pathology and the University of South Australia, Adelaide, SA 5000, Australia. Electronic address:

Interleukin-3 (IL-3) is an activated T cell product that bridges innate and adaptive immunity and contributes to several immunopathologies. Here, we report the crystal structure of the IL-3 receptor α chain (IL3Rα) in complex with the anti-leukemia antibody CSL362 that reveals the N-terminal domain (NTD), a domain also present in the granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-5, and IL-13 receptors, adopting unique "open" and classical "closed" conformations. Although extensive mutational analyses of the NTD epitope of CSL362 show minor overlap with the IL-3 binding site, CSL362 only inhibits IL-3 binding to the closed conformation, indicating alternative mechanisms for blocking IL-3 signaling. Significantly, whereas "open-like" IL3Rα mutants can simultaneously bind IL-3 and CSL362, CSL362 still prevents the assembly of a higher-order IL-3 receptor-signaling complex. The discovery of open forms of cytokine receptors provides the framework for development of potent antibodies that can achieve a "double hit" cytokine receptor blockade.
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http://dx.doi.org/10.1016/j.celrep.2014.06.038DOI Listing
July 2014

Identification of potent antagonist antibodies against mouse IL-13Rα1 using novel bioassays.

J Immunol Methods 2014 May 3;407:48-57. Epub 2014 Apr 3.

CSL Limited, Parkville, Victoria, Australia. Electronic address:

Interleukin-13 (IL-13) is a cytokine implicated in airway diseases such as asthma and idiopathic pulmonary fibrosis. IL-13 signals through a heterodimeric receptor complex consisting of IL-13Rα1 and IL-4Rα, known as the type II IL-4R. IL-4 also signals through this receptor and as such many of the biological effects of IL-13 and IL-4 are similar. Here we describe the development of two sensitive bioassays to determine the potency of antagonists of the mouse type II IL-4R. Both IL-13 and IL-4 dose-dependently induce CCL17 production from J774 mouse monocytic cells and CCL11 production from NIH3T3 mouse fibroblasts in the presence of TNFα. The assays were optimized to minimize TNFα concentration, cell number and incubation time whilst retaining a suitable signal-to-background ratio. Anti-cytokine antibodies or recombinant soluble receptors completely neutralized IL-13 or IL-4 activity in these bioassays. The J774 assay was used to screen a panel of anti-mIL-13Rα1 antibodies for neutralizing activity against this receptor. We report the identification of the first monoclonal antibodies that bind mouse IL-13Rα1 and neutralize both IL-13-induced and IL-4-induced cellular function. These antibodies should prove useful for determining the effects of neutralizing IL-13Rα1 in mouse models of disease. In addition, these bioassays may be used for measuring the bioactivity of mouse IL-13 and IL-4 and for the discovery of additional antagonists of the mouse IL-13Rα1/IL-4Rα complex.
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http://dx.doi.org/10.1016/j.jim.2014.03.019DOI Listing
May 2014

Soluble IFN receptor potentiates in vivo type I IFN signaling and exacerbates TLR4-mediated septic shock.

J Immunol 2014 May 2;192(9):4425-35. Epub 2014 Apr 2.

Centre for Innate Immunity and Infectious Diseases, Monash Institute of Medical Research, Monash University, Clayton, Victoria 3168, Australia.

Circulating levels of a soluble type I IFNR are elevated in diseases, such as chronic inflammation, infections, and cancer, but whether it functions as an antagonist, agonist, or transporter is unknown. In this study, we elucidate the in vivo importance of the soluble type I IFNAR, soluble (s)IFNAR2a, which is generated by alternative splicing of the Ifnar2 gene. A transgenic mouse model was established to mimic the 10-15-fold elevated expression of sIFNAR2a observed in some human diseases. We generated transgenic mouse lines, designated SolOX, in which the transgene mRNA and protein-expression patterns mirrored the expression patterns of the endogenous gene. SolOX were demonstrated to be more susceptible to LPS-mediated septic shock, a disease model in which type I IFN plays a crucial role. This effect was independent of "classical" proinflammatory cytokines, such as TNF-α and IL-6, whose levels were unchanged. Because the increased levels of sIFNAR2a did not affect the kinetics of the increased interferonemia, this soluble receptor does not potentiate its ligand signaling by improving IFN pharmacokinetics. Mechanistically, increased levels of sIFNAR2a are likely to facilitate IFN signaling, as demonstrated in spleen cells overexpressing sIFNAR2a, which displayed quicker, higher, and more sustained activation of STAT1 and STAT3. Thus, the soluble IFNR is an important agonist of endogenous IFN actions in pathophysiological processes and also is likely to modulate the therapeutic efficacy of clinically administered IFNs.
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http://dx.doi.org/10.4049/jimmunol.1302388DOI Listing
May 2014

Crystallization and preliminary X-ray diffraction analysis of the interleukin-3 alpha receptor bound to the Fab fragment of antibody CSL362.

Acta Crystallogr F Struct Biol Commun 2014 Mar 19;70(Pt 3):358-61. Epub 2014 Feb 19.

Australian Cancer Research Foundation Rational Drug Discovery Centre and Biota Structural Biology Laboratory, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.

Interleukin-3 (IL-3) is a member of the beta common family of cytokines that regulate multiple functions of myeloid cells. The IL-3 receptor-specific alpha subunit (IL3Rα) is overexpressed on stem cells/progenitor cells of patients with acute myeloid leukaemia, where elevated receptor expression correlates clinically with a reduced patient survival rate. The monoclonal antibody (MAb) CSL362 is a humanized MAb derived from the murine MAb 7G3, originally identified for its ability to specifically recognize the human IL-3 receptor and for blocking the signalling of IL-3 in myeloid and endothelial cells. In order to elucidate the molecular mechanism of CSL362 antagonism, a preliminary structure of human IL3Rα in complex with the MAb CSL362 has been determined.
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http://dx.doi.org/10.1107/S2053230X14002593DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3944702PMC
March 2014

EphA4 receptor tyrosine kinase is a modulator of onset and disease severity of experimental autoimmune encephalomyelitis (EAE).

PLoS One 2013 4;8(2):e55948. Epub 2013 Feb 4.

Centre for Neuroscience Research, The University of Melbourne, Victoria, Australia.

The EphA4 receptor tyrosine kinase is a major regulator of axonal growth and astrocyte reactivity and is a possible inflammatory mediator. Given that multiple sclerosis (MS) is primarily an inflammatory demyelinating disease and in mouse models of MS, such as experimental autoimmune encephalomyelitis (EAE), axonal degeneration and reactive gliosis are prominent clinical features, we hypothesised that endogenous EphA4 could play a role in modulating EAE. EAE was induced in EphA4 knockout and wildtype mice using MOG peptide immunisation and clinical severity and histological features of the disease were then compared in lumbar spinal cord sections. EphA4 knockout mice exhibited a markedly less severe clinical course than wildtype mice, with a lower maximum disease grade and a slightly later onset of clinical symptoms. Numbers of infiltrating T cells and macrophages, the number and size of the lesions, and the extent of astrocytic gliosis were similar in both genotypes; however, EphA4 knockout mice appeared to have decreased axonal pathology. Blocking of EphA4 in wildtype mice by administration of soluble EphA4 (EphA4-Fc) as a decoy receptor following induction of EAE produced a delay in onset of clinical symptoms; however, most mice had clinical symptoms of similar severity by 22 days, indicating that EphA4 blocking treatment slowed early EAE disease evolution. Again there were no apparent differences in histopathology. To determine whether the role of EphA4 in modulating EAE was CNS mediated or due to an altered immune response, MOG primed T cells from wildtype and EphA4 knockout mice were passively transferred into naive recipient mice and both were shown to induce disease of equivalent severity. These results are consistent with a non-inflammatory, CNS specific, deleterious effect of EphA4 during neuroinflammation that results in axonal pathology.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0055948PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3563632PMC
July 2013

Characterization of the type I interferon locus and identification of novel genes.

Genomics 2004 Aug;84(2):331-45

Center for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia.

The human type I interferon (IFN) genes are clustered on human chromosome 9p21 and the mouse genes are located in the region of conserved synteny on mouse chromosome 4. We have identified two novel mouse Ifna genes (Ifna12, Ifna13) and Ifnl2 (IFN-like 2, a homologue of Limitin/IFN-like 1). Another type I IFN gene was designated Ifne1. Mouse Ifne1 was expressed in ovaries and uterus but not in tissues of hematopoietic origin. IFN-epsilon1 has general structural characteristics of a type I IFN. These studies represent the first detailed annotation of the mouse type I IFN locus, and the products of these novel genes may have important functions in reproduction and host defense.
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http://dx.doi.org/10.1016/j.ygeno.2004.03.003DOI Listing
August 2004

Identification and characterization of polymorphisms at the HAS alpha1-acid glycoprotein (ORM*) gene locus in Caucasians.

Genet Mol Res 2002 Mar 31;1(1):96-105. Epub 2002 Mar 31.

Centre for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Melbourne, Victoria 3168, Australia.

Human alpha(1)-acid glycoprotein (AGP) or orosomucoid (ORM) is a major acute phase protein that is thought to play a crucial role in maintaining homeostasis. Human AGP is the product of a cluster of at least two adjacent genes located on HSA chromosome 9. Using a range of restriction endonucleases we have investigated DNA variation at the locus encoding the AGP genes in a group of healthy Caucasians. Polymorphisms were identified using BamHI, EcoRI, BglII, PvuII, HindIII, TaqI and MspI. Nonrandom associations were found between the BamHI, EcoRI and BglII RFLPs. The RFLPs detected with PvuII, TaqI and MspI were all located in exon 6 of both AGP genes. The duplication of an AGP gene was observed in 11% of the individuals studied and was in linkage disequilibrium with the TaqI RFLP. The identification and characterization of these polymorphisms should prove useful for other population and forensic studies.
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March 2002

Characterization and transcriptional analysis of the mouse Chromosome 16 cytokine receptor gene cluster.

Mamm Genome 2003 Feb;14(2):105-18

Centre for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Clayton, Victoria 3168, Australia.

The class II cytokine receptor (CIICR) genes Il10r2 and Ifnar1 are localized on mouse Chr 16 in a cluster that also contains the CIICR genes Ifnar2 and Ifngr2. The structure of the Il10r2 gene was deduced and consisted of 7 exons and 6 introns arrayed in an organization similar to its human ortholog. We also present a revised Il10r2 cDNA sequence with a total of 100 bp of additional nucleotide sequence in the 5' and 3' untranslated regions, and report the first extensive profiles of Il10r2 and Ifnar1 mRNA developmental stage and adult tissue expression. Promoter-luciferase reporter constructs were used to define the major region (-108 to +67) that conferred basal expression of the Il10r2 gene. Long-range comparative genomic sequence analysis between the mouse and the orthologous human CIICR genomic loci revealed several conserved non-coding regions. The most proximal conserved non-coding sequence was a 204-bp element located 1.6 kb upstream of the transcriptional start site of Ifnar2 that had repressor-like activity in transient transfection assays with an SV40 promoter-luciferase reporter construct. The identification of multiple conserved non-coding sequences will provide the basis for further investigations to elucidate CIICR gene regulation.
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http://dx.doi.org/10.1007/s00335-002-2225-0DOI Listing
February 2003

Multiple regions within the promoter of the murine Ifnar-2 gene confer basal and inducible expression.

Biochem J 2002 Jul;365(Pt 2):355-67

Center for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Melbourne, Victoria 3168, Australia.

The (murine) type I interferon (IFN) receptor, muIfnar-2, is expressed ubiquitously, and exists as both transmembrane and soluble forms. In the present study we show that the gene encoding muIfnar-2 spans approx. 33 kb on mouse chromosome 16, and consists of nine exons and eight introns. The three mRNA splice variants resulting in one transmembrane (muIfnar-2c) and two soluble (muIfnar-2a/2a') mRNA isoforms are generated by alternative RNA processing of the muIfnar-2 gene. Treatment of a range of murine cell lines with a combination of type I and II IFN showed that the muIfnar-2a and -2c mRNA isoforms were up-regulated independently of each other in L929 fibroblasts and hepa-1c1c7 hepatoma cells, but not in M1 myeloid leukaemia cells. Analysis of the 5' flanking region of muIfnar-2 using promoter-luciferase reporter constructs defined three regulatory regions: a region proximal to exon 1, conferring high basal expression, a distal region conferring inducible expression, and a negative regulatory region between the two. These data represent the first promoter analysis of a type I IFN receptor and, taken together with our previous data demonstrating high expression levels and dual biological functions for muIfnar-2a protein, suggests that the regulation of muIfnar-2 isoform expression may be an important way of modulating type I IFN responses.
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http://dx.doi.org/10.1042/BJ20020105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1222688PMC
July 2002
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