Moore M W, Crispe I N, Bevan M J
Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA 92037.
Eur J Immunol. 1989 Aug;19(8):1501-4. doi: 10.1002/eji.1830190824.
The role of T cell receptor (TcR) gamma genes in T cell development has not been determined. To extend our understanding of the repertoire of TcR gamma expression, we prepared a cDNA library from CD4-CD8- adult BALB/c thymocytes and cloned and sequenced 15 TcR gamma genes from this cDNA library. We found that two clones were transcripts of the unrearranged C gamma 2 gene and that three clones terminated in the J gamma 2 region. Nine of the remaining clones were V gamma 1.2 J gamma 2 C gamma 2 genes and five of these were in frame. Only one clone corresponded to C gamma 1 and resulted from an in-frame V gamma 2 J gamma 1 C gamma 1 join. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the gamma chain proteins from the surface of both BALB/c and C57BL/6 adult CD4-CD8- thymocytes did not detect the 32-kDa V gamma 1.2 C gamma 2 protein, but did detect the 35-kDa V gamma C gamma 1 protein. These results suggest that despite the abundance of full-length functional V gamma 1.2 C gamma 2 transcripts in the thymocyte subset, the protein product is not expressed on the cell surface as the predicted 32-kDa gamma protein. Finally, our analysis of the V-J joining of the gamma genes reveals both flexibility at the V-J junction and extensive N-region nucleotide addition that lead to diversity of the predicted protein sequence.
T细胞受体（TcR）γ基因在T细胞发育中的作用尚未确定。为了拓展我们对TcRγ表达谱的理解，我们从成年BALB/c小鼠的CD4-CD8-胸腺细胞中制备了一个cDNA文库，并从该cDNA文库中克隆并测序了15个TcRγ基因。我们发现两个克隆是未重排的Cγ2基因的转录本，三个克隆在Jγ2区域终止。其余九个克隆是Vγ1.2 Jγ2 Cγ2基因，其中五个读框正确。只有一个克隆对应于Cγ1，是由读框正确的Vγ2 Jγ1 Cγ1连接产生的。对成年BALB/c和C57BL/6小鼠CD4-CD8-胸腺细胞表面γ链蛋白进行的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析未检测到32 kDa的Vγ1.2 Cγ2蛋白，但检测到了35 kDa的VγCγ1蛋白。这些结果表明，尽管在该胸腺细胞亚群中存在大量全长功能性Vγ1.2 Cγ2转录本，但该蛋白产物并未以预测的32 kDaγ蛋白形式表达在细胞表面。最后，我们对γ基因V-J连接的分析揭示了V-J连接处的灵活性以及广泛的N区核苷酸添加，这导致了预测蛋白序列的多样性。
