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pubmed:abstractText |
V(D)J recombination requires a pair of signal sequences with spacer lengths of 12 and 23 base pairs. Cleavage by the RAG1 AND RAG2 proteins was previously shown to demand only a single signal sequence. Here, we established conditions where 12- and 23-spacer signal sequences are both necessary for cleavage. Coupled cutting at both sites requires only the RAG1 and RAG2 proteins, but depends on the metal ion. In Mn2+, a single signal sequence supports efficient double strand cleavage, but cutting in Mg2+ requires two signal sequences and is best with the canonical 12/23 pair. Thus, the RAG proteins determine both aspects of the specificity of V(D)J recombination, the recognition of a single signal sequence and the correct 12/23 coupling in a pair of signals.
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pubmed:affiliation |
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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