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Catalytic and Noncatalytic Roles of the CtIP Endonuclease in Double-Strand Break End Resection.

Makharashvili, Nodar and Tubbs, Anthony T. and Yang, Soo-Hyun and Wang, Hailong and Barton, Olivia and Zhou, Yi and Deshpande, Rajashree A. and Lee, Ji-Hoon and Löbrich, Markus and Sleckman, Barry P. and Wu, Xiaohua and Paull, Tanya T. :
Catalytic and Noncatalytic Roles of the CtIP Endonuclease in Double-Strand Break End Resection.
In: Molecular cell, 54 (6) pp. 1022-33. ISSN 1097-4164
[Article] , (2014)

Abstract

The carboxy-terminal binding protein (CtBP)-interacting protein (CtIP) is known to function in 5' strand resection during homologous recombination, similar to the budding yeast Sae2 protein, but its role in this process is unclear. Here, we characterize recombinant human CtIP and find that it exhibits 5' flap endonuclease activity on branched DNA structures, independent of the MRN complex. Phosphorylation of CtIP at known damage-dependent sites and other sites is essential for its catalytic activity, although the S327 and T847 phosphorylation sites are dispensable. A catalytic mutant of CtIP that is deficient in endonuclease activity exhibits wild-type levels of homologous recombination at restriction enzyme-generated breaks but is deficient in processing topoisomerase adducts and radiation-induced breaks in human cells, suggesting that the nuclease activity of CtIP is specifically required for the removal of DNA adducts at sites of DNA breaks.

Item Type: Article
Erschienen: 2014
Creators: Makharashvili, Nodar and Tubbs, Anthony T. and Yang, Soo-Hyun and Wang, Hailong and Barton, Olivia and Zhou, Yi and Deshpande, Rajashree A. and Lee, Ji-Hoon and Löbrich, Markus and Sleckman, Barry P. and Wu, Xiaohua and Paull, Tanya T.
Title: Catalytic and Noncatalytic Roles of the CtIP Endonuclease in Double-Strand Break End Resection.
Language: English
Abstract:

The carboxy-terminal binding protein (CtBP)-interacting protein (CtIP) is known to function in 5' strand resection during homologous recombination, similar to the budding yeast Sae2 protein, but its role in this process is unclear. Here, we characterize recombinant human CtIP and find that it exhibits 5' flap endonuclease activity on branched DNA structures, independent of the MRN complex. Phosphorylation of CtIP at known damage-dependent sites and other sites is essential for its catalytic activity, although the S327 and T847 phosphorylation sites are dispensable. A catalytic mutant of CtIP that is deficient in endonuclease activity exhibits wild-type levels of homologous recombination at restriction enzyme-generated breaks but is deficient in processing topoisomerase adducts and radiation-induced breaks in human cells, suggesting that the nuclease activity of CtIP is specifically required for the removal of DNA adducts at sites of DNA breaks.

Journal or Publication Title: Molecular cell
Volume: 54
Number: 6
Divisions: 10 Department of Biology
10 Department of Biology > Radiation Biology and DNA Repair
Date Deposited: 27 May 2014 11:28
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