DNA mismatch repair (MMR) plays a number of critical roles in eukaryotic cells including: 1) suppression of mutations that result from misincorporation errors during DNA replication as well as chemical damage to DNA and DNA precursors;2) preventing genome rearrangements due to recombination between divergent DNA sequences;3) repair of mispaired bases in recombination intermediates;and 4) DNA damage signaling linked to cellular responses such as cell cycle control and cell death. As a consequence, MMR defects cause increased rates of accumulating mutations and altered recombination events resulting in a characteristic genome instability signature as well as increased resistance to killing by some DNA damaging agents. Because MMR is defective in both inherited and sporadic cancers, understanding MMR will impact human health for a number of reasons: 1) a better understanding of the genetic consequences of MMR defects will impact the development of clinical tests for the MMR status of patients and tumors;and, 2) MMR defects result in resistance to many chemotherapeutic agents so understanding MMR and MMR defects could lead to improvements in cancer therapy. The goal of this proposal is to use Saccharomyces cerevisiae to study the biochemical and genetic mechanisms of the eukaryotic MutS and MutL homologue-dependent MMR pathways. The following lines of experimentation will be carried out: 1) genetic studies will identify MMR genes and proteins that function in redundant and overlapping MMR sub-pathways, which will guide biochemical studies of MMR;2) cell biology and genomic approaches will be used to elucidate the mechanism of coupling of MMR to DNA replication;3) biophysical and genetic approaches will define the protein-protein interactions and conformational changes that underlie the specificity of MMR;4) partial and complete MMR reactions will be reconstituted in vitro using purified proteins to study the mechanisms of MMR;and 5) collaborative mouse model studies will be continued to extend insights from studies with S. cerevisiae to mammalian systems, with a particular focus on studying polygenic interactions and redundant MMR sub-pathways. The ultimate goal of these experiments is to understand the biochemical mechanisms of MMR and how cells utilize MMR to prevent mutations and genome rearrangements. A key feature of these studies is the use of S. cerevisiae to explore questions raised by the genetics of human cancer susceptibility, and collaborative mouse studies to explore the broader implications of results developed in S. cerevisiae. As a consequence, these studies will provide insights into the genetics of human cancer susceptibility and the biology of MMR defects in human cancers in addition to providing a basic understanding of MMR mechanisms.
Project Narrative Inherited defects in mismatch repair (MMR) genes cause a common form of inherited cancer susceptibility and a proportion of many types of human cancer are MMR defective. This project will identify the genes encoding MMR proteins and elucidate the biochemical mechanisms of MMR. These insights will lead to new tools for cancer diagnostics as well as insights for use in improving the efficacy of known chemotherapeutic agents as well as for use in the development of new therapeutic approaches.
|Goellner, Eva M; Smith, Catherine E; Campbell, Christopher S et al. (2014) PCNA and Msh2-Msh6 activate an Mlh1-Pms1 endonuclease pathway required for Exo1-independent mismatch repair. Mol Cell 55:291-304|
|Campbell, Christopher S; Hombauer, Hans; Srivatsan, Anjana et al. (2014) Mlh2 is an accessory factor for DNA mismatch repair in Saccharomyces cerevisiae. PLoS Genet 10:e1004327|
|Srivatsan, Anjana; Bowen, Nikki; Kolodner, Richard D (2014) Mispair-specific recruitment of the Mlh1-Pms1 complex identifies repair substrates of the Saccharomyces cerevisiae Msh2-Msh3 complex. J Biol Chem 289:9352-64|
|Hura, Greg L; Tsai, Chi-Lin; Claridge, Shelley A et al. (2013) DNA conformations in mismatch repair probed in solution by X-ray scattering from gold nanocrystals. Proc Natl Acad Sci U S A 110:17308-13|
|Smith, Catherine E; Mendillo, Marc L; Bowen, Nikki et al. (2013) Dominant mutations in S. cerevisiae PMS1 identify the Mlh1-Pms1 endonuclease active site and an exonuclease 1-independent mismatch repair pathway. PLoS Genet 9:e1003869|
|Bowen, Nikki; Smith, Catherine E; Srivatsan, Anjana et al. (2013) Reconstitution of long and short patch mismatch repair reactions using Saccharomyces cerevisiae proteins. Proc Natl Acad Sci U S A 110:18472-7|
|Chow, Brenda Y; Helfer, Anne; Nusinow, Dmitri A et al. (2012) ELF3 recruitment to the PRR9 promoter requires other Evening Complex members in the Arabidopsis circadian clock. Plant Signal Behav 7:170-3|
|Hombauer, Hans; Srivatsan, Anjana; Putnam, Christopher D et al. (2011) Mismatch repair, but not heteroduplex rejection, is temporally coupled to DNA replication. Science 334:1713-6|
|Sawa, Mariko; Kay, Steve A (2011) GIGANTEA directly activates Flowering Locus T in Arabidopsis thaliana. Proc Natl Acad Sci U S A 108:11698-703|
|Helfer, Anne; Nusinow, Dmitri A; Chow, Brenda Y et al. (2011) LUX ARRHYTHMO encodes a nighttime repressor of circadian gene expression in the Arabidopsis core clock. Curr Biol 21:126-33|
Showing the most recent 10 out of 79 publications