Atsuta N, Nishimura H, Nakamura N, Emoto M, Iwatsuki T, Yoshikai Y
Laboratory of Germfree Life, Nagoya University School of Medicine, Japan.
J Immunol. 1995 Jan 15;154(2):676-84.
Because there are limited numbers of V gamma gene segments and most V gamma rearrangements occur within clusters of the J gamma-C gamma genes in mice, gamma-chains display limited diversity compared with other TCR chains. In this study, we examined the nucleotide sequences of the V gamma-J gamma genes expressed in the gamma delta T cells appearing at the inflamed sites after Salmonella infection in DBA/2 mice. Most of the productive gamma gene rearrangements were V gamma 1-J gamma 4, whereas V gamma 2 and a unique V gamma, the 5' region of which was identical with sequences of the V gamma 2 gene, and the 3' region of which was identical with that of the V gamma 1 gene, were found to be rearranged to J gamma 4 gene, albeit at low frequency. Analysis of the ontogenic appearance of the rearrangements in the J gamma 4-C gamma 4 locus revealed that V gamma 2-J gamma 4 gene rearrangement was frequent in fetal thymocytes at the early stage of gestation. Most of the early fetal V gamma 2-J gamma 4 rearrangements exhibited the identical junction, a nonfunctional canonical sequence. The sequence analysis of the coding joint and the reciprocal recombination signal joint suggests that short homology-mediated direct recombination and chromosomal inversion mechanism are involved in fetal V gamma 2-J gamma 4 gene rearrangement. Taken together, our data suggest that the recombination of multiple V gamma segments with J gamma 4 can diversify the V gamma repertoire.
由于小鼠中Vγ基因片段数量有限，且大多数Vγ重排发生在Jγ - Cγ基因簇内，与其他TCR链相比，γ链的多样性有限。在本研究中，我们检测了DBA/2小鼠感染沙门氏菌后炎症部位出现的γδ T细胞中表达的Vγ - Jγ基因的核苷酸序列。大多数有效的γ基因重排是Vγ1 - Jγ4，而Vγ2和一个独特的Vγ（其5'区域与Vγ2基因序列相同，3'区域与Vγ1基因相同）虽重排至Jγ4基因，但频率较低。对Jγ4 - Cγ4基因座重排的个体发育出现情况分析表明，Vγ2 - Jγ4基因重排在妊娠早期的胎儿胸腺细胞中很常见。大多数早期胎儿的Vγ2 - Jγ4重排表现出相同的连接，即一个无功能的典型序列。编码接头和相互重组信号接头的序列分析表明，短同源性介导的直接重组和染色体倒位机制参与了胎儿Vγ2 - Jγ4基因重排。综上所述，我们的数据表明多个Vγ片段与Jγ4的重组可使Vγ库多样化。
