DIFFERENTIAL CHRONOLOGY OF TCRADV2 GENE USE BY ALPHA-CHAINS AND DELTA-CHAINS OF THE MOUSE TCR

The genes coding for TCR alpha and delta chains share the same genetic locus (TCRA/D). The rules governing the utilization of a V gene with the alpha and delta chains have not been established. More specificall y, it is not known whether the position of a gene within the locus inf luences its utilization in alpha and delta TCR. To elucidate these poi nts, we mapped ADV2 genes in the TCRA/D locus of BALB/c mice and analy zed their utilization in TCR alpha and delta transcripts from thymi is olated from mice of different ages. Our results show that all ADV2 gen es can be used by the two chains, but with strikingly different patter ns. Moreover, ADV2 utilization by the alpha chain proceeds in successi ve concentric waves during development, suggesting a progressive regul ation of gene accessibility and utilization. These results support ind ependent control of TCRA and TCRD gene assembly.