期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1993
卷号：90
期号：6
页码：2433-2437
DOI：10.1073/pnas.90.6.2433
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：To ascertain the extent and organization of the germ-line human T-cell receptor (TCR) beta-chain gene repertoire, beta-chain variable region (V beta) genes were mapped by pulsed-field gel electrophoresis, cosmid cloning, and in situ hybridization. Probes derived from the 24 known V beta families were mapped to a total of six Sfi I fragments in DNA samples from multiple individuals representing all possible haplotypes of TCR V- and C (constant)-region insertion/deletion-related polymorphisms. Four of the Sfi I fragments were linked to one another to develop an extended map of the TCR beta-chain gene complex previously localized to chromosome 7q35. The remaining two Sfi I fragments, containing 6 V beta genes, could not be linked to the TCR beta-chain gene complex. Using human-hamster somatic cell hybrids and in situ hybridization, these orphon genes were localized to chromosome 9p. Nucleotide sequences of the orphon V beta genes, derived from cosmid clones, were 93-97% identical to V beta genes in the TCR beta-chain gene complex. Open reading frames in three of the orphon V beta genes were intact as were the recombination signal sequences. As expected, based on their orphon status, none of the V beta genes of chromosome 9 was detected in transcripts containing C beta. These results indicate that the functional germ-line V beta repertoire in humans is substantially (10%) smaller than previously estimated.
