title: The homeodomain region of Rag-1 reveals the parallel mechanisms of bacterial and V(D)J recombination.
abstract: The V(D)J recombinase subunits Rag-1 and Rag-2 mediate assembly of antigen receptor gene segments. We studied the mechanisms of DNA recognition by Rag-1/Rag-2 using surface plasmon resonance. The critical step for signal recognition is binding of Rag-1 to the nonamer. This is achieved by a region of Rag-1 homologous to the DNA-binding domain of the Hin family of bacterial invertases and to homeodomain proteins. Strikingly, the Hin homeodomain can functionally substitute for the Rag-1 homologous region. Rag-1 also interacts with the heptamer but with low affinity. Rag-2 shows no direct binding to DNA. Once the Rag-1/Rag-2 complex is engaged on the DNA, subsequent cleavage is directed by the heptamer sequence. This order of events remarkably parallels mechanisms that mediate transposition in bacteria and nematodes.
authors.affiliation: Ruttenberg Cancer Center, Mount Sinai School of Medicine, New York, New York 10029, USA.
authors.forename: E
authors.initials: E
authors.lastname: Spanopoulou
authors.forename: F
authors.initials: F
authors.lastname: Zaitseva
authors.forename: F H
authors.initials: FH
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Santagata
authors.forename: D
authors.initials: D
authors.lastname: Baltimore
authors.forename: G
authors.initials: G
authors.lastname: Panayotou
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D005075:Biological Evolution; D004254:DNA Nucleotidyltransferases / Q000502:physiology; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000737:chemistry; D005801:Genes, Homeobox; D005803:Genes, Immunoglobulin; D018398:Homeodomain Proteins / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry*; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D011995:Recombination, Genetic; D013329:Structure-Activity Relationship; D014162:Transfection
chemical_list: D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C064658:RAG-1 protein; D004254:DNA Nucleotidyltransferases; C059997:Hin recombinase