A HIGHLY CONSERVED APOPTOTIC SUPPRESSOR GENE IS LOCATED NEAR THE CHICKEN T-CELL RECEPTOR-ALPHA CHAIN CONSTANT-REGION

A cosmid clone containing the chicken T-cell receptor alpha chain cons tant region (TCRAC) was sequenced. The cosmid contains the TCRAC gene, six putative joining gene segments (TCRAJ), and surprisingly, a chick en homologue for the human apoptotic suppressor gene, defender against cell death (DAD1). The DAD1 gene is 6.3 kilobases downstream of the T CRAC gene and has an inverted transcription orientation with respect t o the TCRAC gene. The cDNA for the chicken DAD1 gene is 597 base pairs in length and encodes a highly conserved hydrophobic protein. The pro ximal location of DAD1 to the TCRAC locus has also been confirmed in b oth humans and mouse. The location of the DAD1 gene suggests that DAD1 may play an important role in T-cell related apoptotic activities.