Aguilar L K, Belmont J W
Department of Microbiology and Immunology, Baylor College of Medicine, Houston, TX 77030.
J Immunol. 1991 Feb 15;146(4):1348-52.
Rearrangement and expression of the V gamma 3-J gamma 1 TCR has been found in murine dendritic epidermal cells (DEC) and fetal thymus. By using the polymerase chain reaction technique, V gamma 3-J gamma 1 rearrangements and RNA expression were detected in the murine adult thymus. Individual genomic and cDNA junctions were cloned and sequenced. In genomic DNA, 55% (16/29) of V gamma 3-J gamma 1 junctional sequences had N regions ranging in length from 1 to 12 nucleotides resulting in considerable junctional diversity. Only 5% (2/42) of cDNA sequences had N regions. The canonical DEC sequence represented 36% (15/42) of the cDNA sequences. Thus, fetal-type V gamma 3-J gamma 1 rearrangements lacking N regions were preferentially expressed in adult thymocytes, some of which may be DEC precursors. The developmental stages in which V gamma 3-J gamma 1 rearrangements are generated were studied by using polymerase chain reaction to detect circular rearrangement products. Active V gamma 3-J gamma 1 rearrangement was detected in thymuses from fetal, newborn, and 2-wk-old mice but not in 5-wk or 8-wk-old (adult) mice. V gamma 2, one of the most common V gamma rearrangements in the adult, was found to be actively rearranging to J gamma 1 in the adult thymus. However, V gamma 2-V gamma 3 replacement rearrangement was not found. These results support the hypotheses that adult thymocytes with rearranged V gamma 3-J gamma 1 are persistent from earlier developmental stages and represent a separate lineage from those with V gamma 2-J gamma 1 rearrangements.
已在小鼠树突状表皮细胞（DEC）和胎儿胸腺中发现Vγ3-Jγ1 TCR的重排和表达。通过使用聚合酶链反应技术，在成年小鼠胸腺中检测到Vγ3-Jγ1重排和RNA表达。对单个基因组和cDNA连接区进行了克隆和测序。在基因组DNA中，55%（16/29）的Vγ3-Jγ1连接序列具有长度为1至12个核苷酸的N区，导致相当大的连接多样性。只有5%（2/42）的cDNA序列具有N区。典型的DEC序列占cDNA序列的36%（15/42）。因此，缺乏N区的胎儿型Vγ3-Jγ1重排在成年胸腺细胞中优先表达，其中一些可能是DEC前体。通过使用聚合酶链反应检测环状重排产物，研究了Vγ3-Jγ1重排产生的发育阶段。在胎儿、新生和2周龄小鼠的胸腺中检测到活跃的Vγ3-Jγ1重排，但在5周或8周龄（成年）小鼠中未检测到。Vγ2是成年小鼠中最常见的Vγ重排之一，发现在成年胸腺中与Jγ1发生活跃重排。然而，未发现Vγ2-Vγ3替代重排。这些结果支持以下假设：具有重排的Vγ3-Jγ1的成年胸腺细胞从早期发育阶段持续存在，并且代表了与具有Vγ2-Jγ1重排的细胞不同的谱系。
