We had previously shown that S. cerevisiae SPT4 contributes to the proper localization of evolutionarily conserved centromeric histone H3 variant (CenH3) Cse4p. The major research goal of our laboratory is to investigate the molecular mechanisms that regulate the function of Cse4p and its interacting partners (Scm3p and Histone H4) to mediate faithful chromosome segregation. We investigated the mechanism of Cse4p localization and have established that mislocalization of Cse4p and altered histone stoichiometry lead to defects in chromosome transmission. Our studies have also shown that overexpression Scm3p and its human homolog HJURP leads to genome instability in yeast and human systems. We examined the effect of chromatin modifiers and post-translational modification of kinetochore proteins on the assembly/function of CenH3 chromatin. Our results showed that hypoacetylation state of centromeric histone H4 is critical for faithful chromosome segregation. Our recent results with Cse4p localization and histone dosage in S. cerevisiae are consistent with those in S. pombe, suggesting conservation of the underlying mechanisms. We have also done genome wide screens using heterozygous dipolid strain collection of about 6000 strains of budding yeast to define genes that are haploinsufficient for chromosome stability. Results from these analyses has allowed us to define evolutionarily conserved pathways that maintain genome stability in yeast and humans. Our research on the molecular determinants of faithful chromosome transmission in S. cerevisiae will help us understand analogous processes in humans and their implications in human disease. Our laboratory is uniquely poised to utilize conventional genetic, biochemical, and cell biology approaches, as well as high-throughput genomic analysis for our research projects. We use an array of gene-deletion strains and a colony-picking robot for the identification of possible cancer drug targets and also for genetic screens by synthetic genome analysis (SGA), developed in the laboratory of Charlie Boone (University of Toronto).

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIABC010822-06
Application #
8552845
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
6
Fiscal Year
2012
Total Cost
$1,327,795
Indirect Cost
Name
National Cancer Institute Division of Basic Sciences
Department
Type
DUNS #
City
State
Country
Zip Code
Ohkuni, Kentaro; Takahashi, Yoshimitsu; Basrai, Munira A (2015) Protein purification technique that allows detection of sumoylation and ubiquitination of budding yeast kinetochore proteins Ndc10 and Ndc80. J Vis Exp :e52482
Mishra, Prashant K; Guo, Jiasheng; Dittman, Lauren E et al. (2015) Pat1 protects centromere-specific histone H3 variant Cse4 from Psh1-mediated ubiquitination. Mol Biol Cell 26:2067-79
Lai, Xianning; Beilharz, Traude; Au, Wei-Chun et al. (2013) Yeast hEST1A/B (SMG5/6)-Like Proteins Contribute to Environment-Sensing Adaptive Gene Expression Responses. G3 (Bethesda) 3:1649-59
Haase, Julian; Mishra, Prashant K; Stephens, Andrew et al. (2013) A 3D map of the yeast kinetochore reveals the presence of core and accessory centromere-specific histone. Curr Biol 23:1939-44
Mishra, Prashant K; Ottmann, Alicia R; Basrai, Munira A (2013) Structural integrity of centromeric chromatin and faithful chromosome segregation requires pat1. Genetics 195:369-79
Boeckmann, Lars; Takahashi, Yoshimitsu; Au, Wei-Chun et al. (2013) Phosphorylation of centromeric histone H3 variant regulates chromosome segregation in Saccharomyces cerevisiae. Mol Biol Cell 24:2034-44
Au, Wei Chun; Dawson, Anthony R; Rawson, David W et al. (2013) A novel role of the N terminus of budding yeast histone H3 variant Cse4 in ubiquitin-mediated proteolysis. Genetics 194:513-8
Ainsworth, William B; Hughes, Bridget Todd; Au, Wei Chun et al. (2013) Cytoplasmic localization of Hug1p, a negative regulator of the MEC1 pathway, coincides with the compartmentalization of Rnr2p-Rnr4p. Biochem Biophys Res Commun 439:443-8
Choy, John S; O'Toole, Eileen; Schuster, Breanna M et al. (2013) Genome-wide haploinsufficiency screen reveals a novel role for γ-TuSC in spindle organization and genome stability. Mol Biol Cell 24:2753-63
Stirling, Peter C; Crisp, Matthew J; Basrai, Munira A et al. (2012) Mutability and mutational spectrum of chromosome transmission fidelity genes. Chromosoma 121:263-75

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