IDENTIFICATION AND CHARACTERIZATION OF THE MURINE RAG1 PROMOTER

Rag1 and Rag2 are required for the somatic rearrangement of immunoglob ulin genes and T-cell receptor genes and the subsequent development of B and T cells. We describe the pattern of DNase I hypersensitive site s surrounding the Rag1 gene that accompanies mouse B-cell development and show that one of these sites corresponds to the murine Rag1 promot er. Transcription initiates over a 30 bp region, with approximately 70 % of the transcripts initiating within a 5 bp region. The promoter con tains neither a consensus TATA box nor an initiator, but does contain an AT rich sequence that could serve as a non-consensus TATA box. The Rag1 promoter directs only negligible levels of expression in transien t transfection assays, but when combined with a heterologous enhancer, it is capable of driving significant levels of expression in pre-B ce lls, pre-T cells, and mature B cells. Methylation interference and mut ation analysis reveal that the Rag1 promoter contains binding sites fo r E-box binding proteins, NF-Y proteins, and Ikaros proteins. These fi ndings are discussed with respect to B-cell development and regulation of differential Rag1 expression by the promoter in pre-B, pre-T, and CNS cells. (C) 1998 Elsevier Science Ltd. All rights reserved.