Pelicci P G, Subar M, Weiss A, Dalla-Favera R, Littman D R
Science. 1987 Aug 28;237(4818):1051-5. doi: 10.1126/science.3112943.
The human T cell antigen-receptor gamma chain, which is expressed on the surface of a subpopulation of CD3+ T lymphocytes, exhibits size polymorphism and varies in its ability to form disulfide bonds with a second polypeptide. Analysis of both genomic and complementary DNA clones encoding the human gamma polypeptide shows differences in lengths of the coding portions of the two constant region genes, C gamma 1 and C gamma 2. A single second-exon segment is always present in the C gamma 1 gene. C gamma 2 alleles containing either duplicated or triplicated second-exon segments are present in the normal human population and are expressed as messenger RNAs. Furthermore, a cysteine residue, encoded by the second exon of C gamma 1 and probably involved in interchain disulfide bridging, is absent in all C gamma 2 second-exon segments. These differences between C gamma 1 and the two alleles of C gamma 2 may explain the variability in molecular weight and disulfide bonding of gamma molecules expressed in different cells.
人类T细胞抗原受体γ链表达于CD3⁺T淋巴细胞亚群的表面，表现出大小多态性，并且在与第二条多肽形成二硫键的能力方面存在差异。对编码人类γ多肽的基因组克隆和互补DNA克隆的分析表明，两个恒定区基因Cγ1和Cγ2的编码部分长度存在差异。Cγ1基因中始终存在一个单一的第二外显子片段。正常人群中存在含有重复或三倍体第二外显子片段的Cγ2等位基因，并作为信使RNA表达。此外，Cγ1第二外显子编码的一个半胱氨酸残基可能参与链间二硫键桥接，在所有Cγ2第二外显子片段中均不存在。Cγ1与Cγ2的两个等位基因之间的这些差异可能解释了不同细胞中表达的γ分子在分子量和二硫键结合方面的变异性。
