The overall goal of this research proposal is to reveal the molecular function of RecN, a protein critical to the repair of DNA double-stranded breaks (DSBs) in bacteria. Bacterial RecN proteins share significant homology to the Structural Maintenance of Chromosomes (SMC) family of proteins. Eukaryotic SMC proteins have essential (although not fully understood) housekeeping and tumor suppressor roles in a variety of DNA metabolic processes such as chromosomal condensation, sister chromatid cohesion and recombinational DNA repair. Although extensive genetic evidence underscores the importance of RecN proteins to bacterial genome maintenance, there has been little substantive biochemical investigation into their function and, consequently, the specific reactions requiring RecN have not been identified. We have successfully identified several in vitro activities mediated by the RecN protein including a cohesin function and the stimulation of recombination. We are now positioned to decipher mechanistic details of RecN function in recombinational DNA repair pathways, utilizing a combination of biochemical, biophysical and biological approaches. This project has three specific aims. First, we will further characterize the biochemical and biophysical properties of the RecN protein related to substrate binding and catalysis. Next, we will determine the role of RecN in mediating recombinational repair by using both in vitro pathway reconstitution and genetic screens. And, finally, we will determine the contribution of multiple sequence motifs conserved in all bacterial RecN proteins and shared by eukaryotic SMC orthologs. We anticipate that the results from this work will provide valuable models for understanding the molecular role that eukaryotic SMC proteins play in genome maintenance.

Public Health Relevance

The repair of damaged chromosomes is critical to the genome maintenance of all organisms. The proposed studies will provide valuable models for understanding the molecular role that SMC proteins play in genome maintenance and DNA repair. SMC proteins have essential, albeit poorly understood functions in a variety of house-keeping DNA processes that can cause birth defects, cancer, and premature aging when defective.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM104375-02
Application #
8694055
Study Section
Prokaryotic Cell and Molecular Biology Study Section (PCMB)
Program Officer
Reddy, Michael K
Project Start
2013-07-05
Project End
2018-05-31
Budget Start
2014-06-01
Budget End
2015-05-31
Support Year
2
Fiscal Year
2014
Total Cost
$262,800
Indirect Cost
$82,800
Name
New Mexico State University Las Cruces
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
173851965
City
Las Cruces
State
NM
Country
United States
Zip Code
88003