Variable region genes in the human T-cell rearranging gamma (TRG) locus: V-J junction and homology with the mouse genes.

The locus of the human T cell rearranging gamma (TRG) or T cell receptor gamma chain genes comprises at least 14 variable genes (TRGV) belonging to four subgroups, five joining segments (TRGJ) and two constant region genes (TRGC). Nine V gamma genes belong to subgroup I, whereas subgroups II, III and IV each consists of a single gene respectively designated V9, V10 and V11. T cells expressing the gamma chain (TRG+) and recognized by the anti-Ti gamma A monoclonal antibody have been shown to rearrange the V9 gene. In order to assess the N diversity at the V-J junction in the TRG+ cells, the germline sequences of the segments involved in the V-J rearrangements must be known. In this paper, we report the sequences of the germline V9 and V10 genes. Comparison of the V-J junction and N region from transcripts or rearranged TRG genes belonging to the different subgroups shows no evidence of D segments in the human TRG locus. Sequences of the rearranged V11 gene from the JM cell line and those of the VA and VB pseudogenes, located upstream of V9 and V11 respectively, are given. Our results bring the number of human V gamma genes whose sequence is known to 13 and reveal unexpected homology with the mouse V gamma genes.