CHARACTERIZATION OF A NOVEL DNA-BINDING DOMAIN WITHIN THE AMINO-TERMINAL REGION OF THE RAG-1 PROTEIN

Rag-1 and Rag-2 are the critical components of the V-(D)-J recombinase required for site-specific recombination of the antigen receptor gene s. In this study, we have examined the ability of recombinant (r) Rag- 1 and Rag-2 to bind the recombination signal sequences (WSS) and have determined that rRag-1, but not rRag-2, is able to directly bind DNA. rRAG-1 DNA binding activity was found to reside within a novel amino-t erminal arginine-rich (RR) domain with partial homology to a variety o f nucleic acid binding domains. Although the RR-domain did not demonst rate RSS-specificity, this DNA binding domain may stabilize the intera ction of RAG-1 with, or increase the affinity for, the V-(D)-J recombi nation signals.