Antao A B, Chinchar V G, McConnell T J, Miller N W, Clem L W, Wilson M R
Department of Microbiology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
Immunogenetics. 1999 Apr;49(4):303-11. doi: 10.1007/s002510050497.
Four cDNAs encoding the major histocompatibility complex (MHC) class I alpha chain were isolated from a channel catfish clonal B-cell cDNA library. Sequence analysis suggests these cDNAs represent three different MHC class I loci. All cDNAs encoded conserved residues characteristic of the MHC class I alpha chain: namely, those involved in peptide binding, salt bridges, disulfide bond formation, and glycosylation. Southern blot analyses of individual outbred and second-generation gynogenetic fish indicated the existence of both polygenic and polymorphic loci. Northern blot studies demonstrated that catfish B, T, and macrophage cell lines transcribed markedly higher levels of class I alpha and beta2-microglobulin (beta2m) mRNA than fibroblast cell lines. In addition, immunoprecipitation data showed that a 41 000 Mr glycoprotein (presumably class I alpha) was associated with beta2m on the surface of catfish B cells. This latter finding is the first direct evidence for the cell surface association of beta2m with the MHC class I alpha chain on teleost cells and supports the notion that functional MHC class I proteins exist in teleosts.
从斑点叉尾鮰克隆B细胞cDNA文库中分离出四个编码主要组织相容性复合体（MHC）I类α链的cDNA。序列分析表明，这些cDNA代表三个不同的MHC I类基因座。所有cDNA都编码了MHC I类α链特有的保守残基：即参与肽结合、盐桥、二硫键形成和糖基化的残基。对单个远交和第二代雌核发育鱼的Southern印迹分析表明存在多基因座和多态性基因座。Northern印迹研究表明，鲶鱼B细胞、T细胞和巨噬细胞系转录的I类α链和β2-微球蛋白（β2m）mRNA水平明显高于成纤维细胞系。此外，免疫沉淀数据显示，一种41000 Mr的糖蛋白（可能是I类α链）与鲶鱼B细胞表面的β2m相关联。后一发现是β2m与硬骨鱼细胞上的MHC I类α链在细胞表面关联的首个直接证据，并支持硬骨鱼中存在功能性MHC I类蛋白的观点。
