Functional analysis of the human RAG 2 promoter

Recombination activating genes RAGI and RAG2 are essential components of V( D)J recombination, a process that generates the specific antigen receptors in lymphocytes. To understand the mechanisms underlying the lineage and dev elopmental regulation of transcription of RAG2, we have characterized the h uman RAG2 exon 1A promoter. In this study, a series of deletion constructs were used to isolate the promoter while a linker scanning approach was take n to assess functionally relevant cis elements within the promoter. Two reg ulatory domains were identified. The - 140 to - 123 region is critical for promoter activity in all cell lines tested. Mutations to the putative Ets ( - 122 to - 118) or to the C/EBP (- 137 to - 129) consensus core sequences d id abrogate promoter activity, although specific DNA/protein interactions r emained, as determined by EMSA. The - 69 to - 48 region demonstrates lineag e specific promoter activity. Mutations to an overlapping, BSAP-myb-Ikaros- myb site (- 65 to - 39) resulted in differential promoter activity in human B and T cells. EMSA analysis of this region showed a B cell specific prote in complex. Transfection of BSAP into cell lines trans-activates the human RAG2 promoter. We conclude that transcriptional regulation of the human RAG 2 gene is complex, involving both tissue specific and ubiquitous factors, a nd both proximal and distal regulatory elements. (C) 2000 Elsevier Science Ltd. All rights reserved.