Genomic structure of the whole D-J-C clusters and the upstream region coding V segments of the TRB locus in pig.

In the vertebrate immune system, T cells play a central role in host defense against microbial or viral infection. Previous studies suggested that at least two sets of TRBD-J-C clusters are harbored in the porcine genome. In this study, we determined 212,193 bp of a continuous porcine genomic sequence covering the entire TRBC region. EPHB6, TRPV6, TRY, and ten TRBV genes were conserved in the vicinity of the TRBD-J-C clusters. Interestingly, three TRBD-J-C clusters were identified in this sequence; each TRBD-J-C cluster consisted of one TRBD and seven TRBJ segments, with one TRBC region composed of four exons. The distribution of repetitive sequences and phylogenetic analysis indicated that the TRBD-J-C cluster, located at the center of the three clusters identified, had a structure combined with the others. Most of the TRBJ segments were available in public databases, suggesting that all three TRBD-J-C clusters are functional in pigs.