title: cDNA cloning, genomic structure, molecular characterization and mRNA expression analysis of the Pekin duck interleukin-10 receptor 1.
abstract: Interleukin-10 (IL-10) mediates its broad anti-inflammatory and immunoregulatory effects through two cell surface receptors by which binding to the IL-10 receptor 1 (IL-10R1) is the initial step that leads to recruitment of IL-10R2 and initiation of the ternary complex signal transduction cascade. The duck IL-10R1 (duIL-10R1) cDNA was obtained by using RT-PCR and 5'RACE. The deduced 574 amino acid protein has an amino acid identity of 62%, 27% and 28% with chicken, mouse and human IL-10R1, respectively. Comparison of the duIL-10R1 cDNA with duck genomic sequences revealed a seven exon-six intron structure of the duck IL-10R1 gene that shares a similar size with the respective exons 1-7 of the chicken and human IL-10R1 genes, but the avian genes are more compact. Promoter analysis identified putative binding sites for regulatory elements such as CCAAT enhancer binding protein-α, specificity protein 1 (Sp1), nuclear factor 1 (NF1), transcriptional regulatory protein Oct-1, nuclear factor (NF) κB and interferon-stimulated gene factor-3 (ISGF-3). A canonical TATA box was absent in proximity of the transcription initiation site, but a CpG island was present. Sequence analysis of the predicted duIL-10R1 protein revealed characteristic features of class-II cytokine receptors (CFR2) family members and a considerable degree of conservation of residues implicated in ligand binding across higher vertebrates. The predicted secondary structure of the duIL-10R1 extracellular domain is compatible with the two-subdomain structure of the human IL-10R1 protein established by its crystal structure. The 3D model structure shows conservation of the positions of conserved contact residues within four of the five ligand-binding loops. Within the cytoplasmic domain, residues implicated in signal transduction were conserved including two redundant peptide motifs GYXXQ essential for recruitment and activation of STAT3. DuIL-10R1 mRNA expression was most abundant in spleen, thymus, peripheral blood mononuclear cells (PBMCs) and lung. Mitogen stimulation of PBMCs transiently increased duIL-10R1 mRNA expression. Our observations suggest significant evolutionary conservation of the IL-10R1 genomic organization, protein structure and receptor function through the JAK/STAT signalling pathway across higher vertebrates.
authors.affiliation: Department of Medicine, Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Q
authors.initials: Q
authors.lastname: Yao
authors.forename: K P
authors.initials: KP
authors.lastname: Fischer
authors.forename: D L
authors.initials: DL
authors.lastname: Tyrrell
authors.forename: K S
authors.initials: KS
authors.lastname: Gutfreund
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D019295:Computational Biology; D017124:Conserved Sequence; D018899:CpG Islands; D018076:DNA, Complementary / Q000235:genetics; D004372:Ducks / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D005091:Exons; D006801:Humans; D050832:Interferon-Stimulated Gene Factor 3 / Q000235:genetics / Q000378:metabolism; D053709:Interleukin-10 Receptor alpha Subunit / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015759:Ionomycin / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D010703:Phorbol Esters / Q000494:pharmacology; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D015398:Signal Transduction; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D050832:Interferon-Stimulated Gene Factor 3; D053709:Interleukin-10 Receptor alpha Subunit; D016328:NF-kappa B; D010703:Phorbol Esters; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; C119222:phorbol-12-myristate; D015759:Ionomycin