title: Identification and characterization of a novel splice variant of rhesus macaque MHC IA.
abstract: Major histocompatibility complex class I (MHC I) molecules play a pivotal role in the immune recognition to intracellular pathogens. A number of important splice variants have already been characterized for these molecules in different species, suggesting their important roles in modulation of immune responses. In this study, we have identified and characterized a novel alternatively spliced form of rhesus macaque MHC IA (designated MHC IA-sv2) that lacks exons coding for the α2 and α3 domains. Despite lacking the α2 and α3 domains, MHC IA-sv2 is targeted to the cell surface, as a 23-kDa glycoprotein that is totally susceptible to endoglycosidase-H digestion and is reduced to 18kDa after deglycosylation with PNGase F. In contrast, the full-length MHC IA reaches the cell surface as a 43-kDa protein of form with complex-type N-glycosylation (endoglycosidase-H resistant). Moreover, we provide evidence here that MHC IA-sv2 can self-associate, forming homodimers, or associate with the fully mature MHC IA molecule, forming a heterodimeric structure in mammalian cells. These data demonstrate that the formation of heterodimers may have some functional implications in the fine tuning of MHC IA-mediated innate and adaptive immune responses.
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, PR China.
authors.forename: Zheng-Xi
authors.initials: ZX
authors.lastname: Dai
authors.forename: Gao-Hong
authors.initials: GH
authors.lastname: Zhang
authors.forename: Xi-He
authors.initials: XH
authors.lastname: Zhang
authors.forename: Yong-Tang
authors.initials: YT
authors.lastname: Zheng
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002462:Cell Membrane / Q000235:genetics / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons; D005805:Genes, MHC Class I; D006031:Glycosylation; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008253:Macaca mulatta / Q000235:genetics* / Q000276:immunology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D055503:Protein Multimerization; D011499:Protein Processing, Post-Translational
chemical_list: D018076:DNA, Complementary; D015395:Histocompatibility Antigens Class I