Identification of a novel human T-cell receptor V beta subfamily by genomic cloning.

Although a large number of human TCRBV gene segment sequences have been reported, the extent of the germline repertoire is still not precisely known. Most TCRBV gene segments have been identified in cDNA clones. However, genes expressed on only a small number of peripheral T cells may be more easily detectable by analysis of genomic DNA. In the present study, screening of cosmid clones containing the BV24S1 gene segment revealed the presence of a novel TCRBV gene segment defining a new subfamily, BV25S1. The nucleotide sequence of the gene contained a single open reading frame and encoded structurally important amino acids at correct positions. Southern blot analysis indicated that the BV25 subfamily contained only this single member. A single nucleotide polymorphism was identified by nucleotide sequencing of the gene from multiple individuals. Amplification of rearranged BV25S1 genes from cDNA derived from PBLs confirmed that the BV25S1 gene segment was capable of normal rearrangement and transcription.