CLONING AND CHARACTERIZATION OF THE HUMAN RECOMBINATION-ACTIVATING-GENE-1 (RAG1) AND RAG2 PROMOTER REGIONS

Recombination activating gene 1 (RAG1) and RAG2 are the essential and tissue-specific components of V(D)J recombination. We have characteriz ed the genomic organization of the human RAG locus, mapped the transcr iptional initiation sites, and partially sequenced and performed funct ional reporter assays on the 5' flanking regions of human RAG1 and RAG 2. Transcription initiation sites were mapped by rapid amplification o f 5' cDNA ends, primer extension, and/or RNase protection in normal th ymocytes, three pre-B cell lines, and a mature B cell line. A single p romoter region was used for RAG1 transcription. In contrast, transcrip tion of RAG2 initiates at two distinct regions of the genome. The 5'-f lanking region of the human RAG2 gene is TATA-less; however, there is a GATAA consensus at position -34 with respect to the major transcript ional initiation site of RAG1. Promoter regions of human RAG1 and RAG2 are active in both lymphoid and nonlymphoid cell lines, suggesting th at an outside regulatory element is probably involved in the tissue-sp ecific transcriptional regulation of the RAG genes.