We have used the anchored polymerase chain reaction (A-PCR) to clone and compare the 5' upstream regions of the human T cell receptor gamma (TRG) genes. Whereas little homology was found among subgroups I, II, III and IV, sequence alignment of TRG subgroup I members revealed a high degree of homology in the 5' sequences. A conserved heptamer sequence (CTGCAGG), which was found upstream from the translation initiation site of all TRG genes in our analysis. Determination of the transcription initiation site located the conserved heptamer 65 base pairs upstream from the cap sites of V5. No TATA box or other cis-acting promoter sequences could be identified in any of the human TRG upstream sequences.