科研之友
微信
新浪微博
Facebook
分享链接
摘要
The nucleotide sequence of 77.7 kb from the human T-cell receptor beta-chain locus was determined directly from three overlapping cosmid clones using the primer-walking approach. Computer-aided analyses of this sequence reveal the presence of at least 11 genic regions that are closely related to the human T-cell receptor beta variable region (TCRBV) gene family. These include five germline sequences that have previously been determined, V(beta)21.2, V(beta)8.1, V(beta)8.2, V(beta)8.3, and V(beta)16, and four whose sequences have partially been determined at the mRNA level, V(beta)6, V(beta)23, V(beta)12.2, V(beta)24. The two remaining V(beta) Tcr-related sequences have eluded discovery by cDNA and RT-PCR cloning and genomic blot hybridization methods. These two V(beta) Tcr-related genes lack >75% nucleotide sequence identity with any other V(beta)Tcr gene member and therefore, by convention, are referred to as new subfamily members V(beta)25 and V(beta)26. This lack of shared identity with other subfamily members explains why they were not detected by hybridization. The promoter regions of these V(beta) Tcr genes contain the conserved Tcr decamer element located between 80 and 110 bp 5' of the translation start site, generally near a putative TATAA promoter element. Our sequence analysis also reveals that a 3.3-kb duplication unit was involved in the recombination event that produced the closely related V(beta)8.1 and 8.2 gene subfamily members. This sequenced region of the V(beta) locus contains an average number of repetitive DNA elements (21 Alu, three L1, three MER, and three retrovirus-related elements).
- 出版日期1994-3-15
