The RAG1/RAG2 complex constitutes a 3' flap endonuclease: implications for junctional diversity in V(D)J and transpositional recombination.
During V(D)J recombination, processing of branched coding end intermediates is essential for generating junctional diversity. Here, we report that the RAG1/ RAG2 recombinase is a 3' flap endonuclease. Substrates of this nuclease activity include various coding end intermediates, suggesting a direct role for RAG1/ RAG2 in generating junctional diversity during V(D)J recombination. Evidence is also provided indicating that site-specific RSS nicking involves RAG1/RAG2-mediated processing of a localized flap-like structure, implying 3' flap nicking in multiple DNA processing reactions. We have also demonstrated that the bacterial transposase Tn10 contains a 3' flap endonuclease activity, suggesting a mechanistic parallel between RAG1/RAG2 and other transposases. Based on these data, we propose that numerous transposases may facilitate genomic evolution by removing single-stranded extensions during the processing of excision site junctions.
Santagata
S
S
Ruttenberg Cancer Center, Mount Sinai School of Medicine, New York, New York 10029, USA.
Besmer
E
E
Villa
A
A
Bozzi
F
F
Allingham
J S
JS
Sobacchi
C
C
Haniford
D B
DB
Vezzoni
P
P
Nussenzweig
M C
MC
Pan
Z Q
ZQ
Cortes
P
P
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D014644:Genetic Variation; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D011995:Recombination, Genetic; D019895:Transposases / Q000235:genetics
D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; C499311:RAG2 protein, human; C499308:Rag2 protein, mouse; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein; D004247:DNA; D019895:Transposases