This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Peng, A. Articles by Chen, P.-L. Search for Related Content PubMed PubMed Citation Articles by Peng, A. Articles by Chen, P.-L.

NFBD1/Mdc1 Mediates ATR-Dependent DNA Damage Response

Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas

Requests for reprints: Phang-Lang Chen, University of California, Biological Chemistry, Med Sci 1, Irvine, CA 92697. Phone: 949-824-4008; Fax: 949-824-2688; E-mail: plchen{at}uci.edu.

Budding yeast Rad9 (scRad9) plays a central role in mediating Mec1-dependent phosphorylation by recruiting its downstream substrates. The human scRad9 orthologues 53BP1 and NFBD1 associate with ionizing radiation-induced foci (IRIF) at sites of DNA repair. RNAi-based gene silencing of 53BP1 or NFBD1 has shown impaired phosphorylation of SQ/TQ [ataxia-telangiectasia mutated/ATM and Rad3-related (ATM/ATR) substrates] at IRIF, intra-S, and G₂-M checkpoints and has thereby revealed essential roles for 53BP1 and NFBD1 in the DNA damage signaling pathway. Whether 53BP1 and NFBD1 are required for activation of kinases and/or for recruitment of substrates at IRIF, however, is not clear. Here we show that both 53BP1 and NFBD1 are required for recruitment of ATR to DNA damage sites, as well as for ATR-dependent phosphorylation in response to DNA damage. NFBD1 is not required for ssDNA generation at DNA damage sites and is not recruited by replication protein A (RPA)–coated ssDNA. We therefore show that recruitment of NFBD1 and/or 53BP1, the factors downstream of H2AX, is independent of ssDNA generation and RPA coating, whereas both ssDNA and RPA coating play key roles in regulation of the ATR-dependent pathway. These novel findings help clarify where NFBD1 functions in DNA damage early responses.

Key Words: NFBD1 • MDC1 • 53BP1 • ATR • DNA damage response

This article has been cited by other articles:

				S. Sivasubramaniam, X. Sun, Y.-R. Pan, S. Wang, and E. Y.-H.P. Lee Cep164 is a mediator protein required for the maintenance of genomic stability through modulation of MDC1, RPA, and CHK1 Genes & Dev., March 1, 2008; 22(5): 587 - 600. [Abstract] [Full Text] [PDF]

				E. D. Strome, X. Wu, M. Kimmel, and S. E. Plon Heterozygous Screen in Saccharomyces cerevisiae Identifies Dosage-Sensitive Genes That Affect Chromosome Stability Genetics, March 1, 2008; 178(3): 1193 - 1207. [Abstract] [Full Text] [PDF]

				K. C. Manthey, S. Opiyo, J. G. Glanzer, D. Dimitrova, J. Elliott, and G. G. Oakley NBS1 mediates ATR-dependent RPA hyperphosphorylation following replication-fork stall and collapse J. Cell Sci., December 1, 2007; 120(23): 4221 - 4229. [Abstract] [Full Text] [PDF]

				M. Nakanishi, T. Ozaki, H. Yamamoto, T. Hanamoto, H. Kikuchi, K. Furuya, M. Asaka, D. Delia, and A. Nakagawara NFBD1/MDC1 Associates with p53 and Regulates Its Function at the Crossroad between Cell Survival and Death in Response to DNA Damage J. Biol. Chem., August 3, 2007; 282(31): 22993 - 23004. [Abstract] [Full Text] [PDF]

				J. Verheyde, L. de Saint-Georges, L. Leyns, and M.A. Benotmane The Role of Trp53 in the Transcriptional Response to Ionizing Radiation in the Developing Brain DNA Res, January 1, 2006; 13(2): 65 - 75. [Abstract] [Full Text] [PDF]

				D. Cortez Unwind and slow down: checkpoint activation by helicase and polymerase uncoupling Genes & Dev., May 1, 2005; 19(9): 1007 - 1012. [Full Text] [PDF]