Human cancers arise through a series of genetic changes that transform normal cells into malignant tumors. Many of these changes are caused by genomic rearrangements and other errors during replication. To prevent such replication errors, cells have evolved DNA damage checkpoints, a sophisticated set of DNA quality control mechanisms. Central among them is the S-phase DNA damage checkpoint, a mechanism that slows replication in response to DNA damage. Genetic evidence in humans and mice suggest that the S-phase DNA damage checkpoint is crucial for preventing cancer;human patients with mutations that disrupt this checkpoint are prone to a variety of early-onset malignancies. Understanding the checkpoint's mechanism is essential for understanding the etiology of these cancers, and will fundamentally affect the way subsequent studies of this checkpoint are approached. The checkpoint has two branches: one that regulates the activation of replication origins and one that regulates the progression of replication forks. The mechanism of the fork-regulation branch of the checkpoint is not understood. Furthermore, the relative importance of the two branches in maintaining genomic stability is unknown. The proposed experiments are designed to i) to directly determine the extent to which regulation of origin firing and fork progression contribute to the slowing of replication in response to DNA damage, ii) to test the hypothesis that the fork branch acts to induce replication-coupled recombination and iii) to measure the relative contributions of the two branches to the maintenance of genomic stability. These experiments will take advantage of the fission yeast Schizosaccharomyces pombe as a model system. The conservation of checkpoints between fission yeast and humans makes fission yeast an excellent model for investigating these vital DNA damage surveillance pathways. The powerful genetic and biochemical tools available for fission yeast make it possible to rapidly identify key pathway members and rigorously test hypotheses about their functions. Understanding the fission yeast S-phase DNA damage checkpoint will provide an important framework for understanding how the human checkpoint maintains genomic stability. This understanding will lead to new therapeutic targets and diagnostic tools for the treatment and prevention of human cancer.

Public Health Relevance

Many of the genetic changes that lead to cancer are caused by errors during DNA replication. Cells use the S-phase DNA damage checkpoint to prevent and repair such replication errors. The proposed research will elucidate the function of this checkpoint, allowing for the identification of new therapeutic targets and diagnostic tools for the treatment and prevention of human cancer.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM069957-08
Application #
8248265
Study Section
Molecular Genetics C Study Section (MGC)
Program Officer
Reddy, Michael K
Project Start
2004-07-01
Project End
2014-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
8
Fiscal Year
2012
Total Cost
$325,710
Indirect Cost
$127,710
Name
University of Massachusetts Medical School Worcester
Department
Biochemistry
Type
Schools of Medicine
DUNS #
603847393
City
Worcester
State
MA
Country
United States
Zip Code
01655
Yu, Zhi-Yong; Zhang, Meng-Ting; Wang, Gao-Yuan et al. (2013) Fission yeast nucleolar protein Dnt1 regulates G2/M transition and cytokinesis by downregulating Wee1 kinase. J Cell Sci 126:4995-5004
Rhind, Nicholas; Gilbert, David M (2013) DNA replication timing. Cold Spring Harb Perspect Biol 5:a010132
Rhind, Nicholas; Gilbert, David M (2013) DNA Replication Timing. Cold Spring Harb Perspect Med 3:1-26
Tsankov, Alex; Yanagisawa, Yoshimi; Rhind, Nicholas et al. (2011) Evolutionary divergence of intrinsic and trans-regulated nucleosome positioning sequences reveals plastic rules for chromatin organization. Genome Res 21:1851-62
Willis, Nicholas; Rhind, Nicholas (2011) Studying G2 DNA damage checkpoints using the fission yeast Schizosaccharomyces pombe. Methods Mol Biol 782:1-12
Limbo, Oliver; Porter-Goff, Mary E; Rhind, Nicholas et al. (2011) Mre11 nuclease activity and Ctp1 regulate Chk1 activation by Rad3ATR and Tel1ATM checkpoint kinases at double-strand breaks. Mol Cell Biol 31:573-83
Willis, Nicholas; Rhind, Nicholas (2011) Studying S-phase DNA damage checkpoints using the fission yeast Schizosaccharomyces pombe. Methods Mol Biol 782:13-21
Willis, Nicholas; Rhind, Nicholas (2010) The fission yeast Rad32(Mre11)-Rad50-Nbs1 complex acts both upstream and downstream of checkpoint signaling in the S-phase DNA damage checkpoint. Genetics 184:887-97
Rhind, Nicholas; Yang, Scott Cheng-Hsin; Bechhoefer, John (2010) Reconciling stochastic origin firing with defined replication timing. Chromosome Res 18:35-43
Rhind, Nicholas (2009) Changing of the guard: how ATM hands off DNA double-strand break signaling to ATR. Mol Cell 33:672-4

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