The goal of these proposed studies is to understand the molecular mechanism of homologous genetic recombination in mammalian cells. Homologous recombination plays an integral role in maintaining genomic stability and is an important mechanism for the repair of chromosomal double-strand breaks resulting from exposure to ionizing radiation. Our work focuses on the functional organization of domains within the human Rad52 protein (HsRad52) as well as the functional relationship(s) between HsRad52 and other human recombination proteins. Despite significant similarities in the overall mechanism of DNA strand exchange in bacteria, yeast and higher eukaryotes, the larger number of components involved in the regulation and catalysis of recombination in vertebrates suggests a considerably more complex process. We have identified a new self-association domain and a potential second DNA binding site within HsRad52. Our studies will address the functional relevance of these and other protein domains both in vitro and in vivo. Genetic studies will be performed using chicken B cell lines in which mutant RAD alleles are complemented by their human counterpart. We will also investigate the use of RNAi for our genetic studies. This combination of methods will provide important insights into specific biochemical aspects of HsRad52 that are required for optimal function in vivo. Understanding the molecular mechanistic principles of homologous recombination in humans has far-reaching effects for creating novel proteins with desired properties that may be used for prevention of diseases resulting from genomic instability and for beneficial genetic manipulation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM065851-01A1S1
Application #
6946064
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Anderson, Richard A
Project Start
2004-05-01
Project End
2008-04-30
Budget Start
2004-05-01
Budget End
2005-04-30
Support Year
1
Fiscal Year
2004
Total Cost
$22,680
Indirect Cost
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
Sage, Jay M; Gildemeister, Otto S; Knight, Kendall L (2010) Discovery of a novel function for human Rad51: maintenance of the mitochondrial genome. J Biol Chem 285:18984-90
Gildemeister, Otto S; Sage, Jay M; Knight, Kendall L (2009) Cellular redistribution of Rad51 in response to DNA damage: novel role for Rad51C. J Biol Chem 284:31945-52
Bennett, Brian T; Bewersdorf, Jorg; Knight, Kendall L (2009) Immunofluorescence imaging of DNA damage response proteins: optimizing protocols for super-resolution microscopy. Methods 48:63-71
Bewersdorf, Jorg; Bennett, Brian T; Knight, Kendall L (2006) H2AX chromatin structures and their response to DNA damage revealed by 4Pi microscopy. Proc Natl Acad Sci U S A 103:18137-42
Bennett, Brian T; Knight, Kendall L (2005) Cellular localization of human Rad51C and regulation of ubiquitin-mediated proteolysis of Rad51. J Cell Biochem 96:1095-109