Wilson M R, Zhou H, Bengtén E, Clem L W, Stuge T B, Warr G W, Miller N W
Department of Microbiology, University of Mississippi Medical Center, Jackson 39216, USA.
Mol Immunol. 1998 Jun;35(9):545-57. doi: 10.1016/s0161-5890(98)00037-6.
Herein are reported full length cDNA sequences for TCR alpha- and beta-chains of the channel catfish. Included are sequences belonging to four Valpha and six Vbeta families which share hallmarks in common with the Valpha and Vbeta genes of other species. Similar to the situation in other vertebrates, the catfish Calpha and Cbeta sequences exhibit distinct immunoglobulin, connecting peptide, transmembrane and cytoplasmic domains. However, the catfish TCR Calpha and Cbeta regions are shorter than those of mammals and the catfish Cbeta chain lacks a cysteine in its connecting peptide region. Two different catfish Cbeta cDNA sequences were identified, suggesting the existence of either two Cbeta loci or allotypes. Based on Southern blot analyses, each of the catfish TCR gene loci appear to be arranged in a translocon (as opposed to multicluster) organization with multiple V elements and a single or few copies of C region DNA. At the deduced amino acid level, the catfish Cbeta sequence exhibits 42% identity with the Cbeta of Atlantic salmon, 41% identity with the Cbeta of rainbow trout and 26% identity with Cbeta of the horned shark. The catfish Calpha amino acid sequence exhibits 44 and 29% identity with Calpha of the rainbow trout and southern pufferfish, respectively. TCRalpha and beta messages are selectively expressed and rearranged in a catfish clonal cell line that appears to be of the T lineage. This TCR alpha/beta expressing clonal lymphocyte line, designated 28S.1, has T-cell like function in that it constitutively produces a supernatant factor(s) with growth promoting activity. These findings should facilitate functional studies of fish TCRs and T cells in ways not previously possible with other 'lower' vertebrate models.
本文报道了斑点叉尾鮰TCRα和β链的全长cDNA序列。其中包括属于四个Vα和六个Vβ家族的序列，这些序列与其他物种的Vα和Vβ基因具有共同特征。与其他脊椎动物的情况类似，鲶鱼的Cα和Cβ序列表现出不同的免疫球蛋白、连接肽、跨膜和细胞质结构域。然而，鲶鱼的TCR Cα和Cβ区域比哺乳动物的短，并且鲶鱼的Cβ链在其连接肽区域缺乏一个半胱氨酸。鉴定出两种不同的鲶鱼Cβ cDNA序列，表明存在两个Cβ基因座或同种异型。基于Southern印迹分析，每个鲶鱼TCR基因座似乎以转座子（与多簇相对）组织形式排列，具有多个V元件和单个或少数拷贝的C区DNA。在推导的氨基酸水平上，鲶鱼的Cβ序列与大西洋鲑的Cβ具有42%的同一性，与虹鳟的Cβ具有41%的同一性，与角鲨的Cβ具有26%的同一性。鲶鱼的Cα氨基酸序列与虹鳟和南方河豚的Cα分别具有44%和29%的同一性。TCRα和β信息在一个似乎是T谱系的鲶鱼克隆细胞系中被选择性表达和重排。这个表达TCRα/β的克隆淋巴细胞系，命名为28S.1，具有类似T细胞的功能，因为它组成性地产生具有生长促进活性的上清因子。这些发现应该能够以前所未有的方式促进对鱼类TCR和T细胞的功能研究，而这在其他“低等”脊椎动物模型中是不可能的。
