A NOVEL ARTEMIS/DNA-DEPENDENT PROTEIN KINASE COMPLEX AND METHODS OF USE THEREOF

摘要

In the present invention, it is disclosed that Artemis forms a complex with the 469 kDa DNA-dependent protein kinase (DNA-PK>cs<) in vitro and in vivo in the absence of DNA. The purified Artemis protein alone possesses single-strand specific 5' to 3' exonuclease activity. Upon complex formation, DNA-PK>cs< phosphorylates Artemis, and Artemis acquires endonucleolytic activity with respect to single-stranded nucleotides, including 5' and 3' overhangs, as well as hairpins. Further, the Artemis:DNA-PKcs complex can open hairpins generated by the RAG complex from a 12/23-substrate pair. Thus, DNA-PK>cs< regulates Artemis by both phosphorylation and complex formation to permit enzymatic activities that are critical for the hairpin opening step of V(D)J recombination and for all of the 5'and 3'overhang processing in nonhomologous DNA end joining.