ORGANIZATION OF THE V-GENE SEGMENTS IN MOUSE T-CELL ANTIGEN RECEPTOR ALPHA DELTA-LOCUS/

The mouse T-cell receptor (TCR) alpha/delta locus was mapped using 17 V alpha and 4 V delta subfamily-specific probes. Four complementary me thods were used: (1) an estimate of the V gene repertoire by Southern blot analysis of genomic DNA with subfamily-specific probes; (2) an an alysis of V gene segments deleted by TCR gene rearrangements from a pa nel of T-cell tumors and hybridomas; (3) an analysis of overlapping cl usters of cosmid clones; and (4) an analysis of large DNA fragments se parated by field-inversion gel electrophoresis. The alpha/delta locus spans about 1 Mb. The distance between the 3'-most V gene segment (V d elta 1) and the delta constant gene (C delta) is no more than 150 kb. Sixty-six V gene segments have been mapped physically on cosmids. The members of individual V alpha gene segment subfamilies are dispersed t hroughout the locus. In contrast, the V delta gene segments V delta 1 to 5 are clustered at the 3' end of the V gene segment cluster. At lea st two DNA segment duplications, 45 to 80 kb in length, are present in the locus. These data provide information on the evolution of the (al pha/delta) locus and on organizational features that might influence t he expression of specific V gene segments in gamma delta cells. (C) 19 94 Academic Press,Inc.