The long-term objectives of this research are to use the special opportunities available in Saccharomyces and related species to bring an understanding of epigenetic processes to a much deeper level, exploiting innovative approaches developed in the present review period in ways that are inaccessible in other organisms. The PI has developed an assay that captures the transient and temporary expression of epigenetically silenced genes, making a permanent and heritable mark of that transient expression. This assay will be used to identify comprehensively every genetic contribution to the stability of epigenetic silencing, which has never before been possible. The assay will be adapted to allow a critical test of the leading model for the inheritance of silenced chromatin. New data at much higher resolution than that of earlier studies have called into question all previous ideas of how heterochromatin, or other chromatin structures, spread from sites of nucleation. Systematic evaluation of the structure of silenced chromatin as it is formed will test whether existing models can be adapted, or need to be replaced. In keeping with the emerging importance of metabolic intermediates as mediators of epigenetics and cancer, the PI will resolve the paradoxical role of Sir2, the founding member of the sirtuin family of deacetylases, with respect to the potential role of 2-O-acetyl-ADP-ribose in silencing. The mechanism(s) operating to repress gene expression in silenced chromatin are not yet known. The PI will use the RNA polymerase from phage T7 to dig deep into the mechanism(s) of repression in silenced chromatin, along with tests of the contribution of specific transcription factors to the silencing process. Nutrition is the single most important translational interface between the environment and the epigenome, with folate playing a central role. The impact of folate limitation on the structure of yeast and human epigenomes will be determined to reveal the extent and mechanism by which nutritional limitation alters the expression of the genome. Finally, a newly developed yeast species, optimally chosen for the purpose, will be used to learn how Sir-based silencing and RNAi-based silenced cooperate or compete, and then separated during speciation.

Public Health Relevance

Epigenetic processes are fundamental to development and are increasingly recognized as playing critical roles in diseases ranging from malaria to cancer. This work will determine what keeps epigenetic states stable, how nutrition affects the epigenome, especially in the 9% of people with a heritable defect in folate metabolism, and whether a metabolite produced by the now famous family of Sirtuin enzymes has a role in gene silencing..

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM031105-32
Application #
8579744
Study Section
Molecular Genetics B Study Section (MGB)
Program Officer
Carter, Anthony D
Project Start
1982-07-01
Project End
2017-06-30
Budget Start
2013-09-01
Budget End
2014-06-30
Support Year
32
Fiscal Year
2013
Total Cost
$543,779
Indirect Cost
$177,766
Name
University of California Berkeley
Department
Miscellaneous
Type
Organized Research Units
DUNS #
124726725
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Sieverman, Kathryn J; Rine, Jasper (2018) Impact of Homologous Recombination on Silent Chromatin in Saccharomyces cerevisiae. Genetics 208:1099-1113
Janke, Ryan; King, Grant A; Kupiec, Martin et al. (2018) Pivotal roles of PCNA loading and unloading in heterochromatin function. Proc Natl Acad Sci U S A 115:E2030-E2039
Janke, Ryan; Iavarone, Anthony T; Rine, Jasper (2017) Oncometabolite D-2-Hydroxyglutarate enhances gene silencing through inhibition of specific H3K36 histone demethylases. Elife 6:
McCleary, David F; Rine, Jasper (2017) Nutritional Control of Chronological Aging and Heterochromatin in Saccharomyces cerevisiae. Genetics 205:1179-1193
Schlissel, Gavin; Krzyzanowski, Marek K; Caudron, Fabrice et al. (2017) Aggregation of the Whi3 protein, not loss of heterochromatin, causes sterility in old yeast cells. Science 355:1184-1187
Dodson, Anne E; Rine, Jasper (2016) Donor Preference Meets Heterochromatin: Moonlighting Activities of a Recombinational Enhancer in Saccharomyces cerevisiae. Genetics 204:1065-1074
Ellahi, Aisha; Rine, Jasper (2016) Evolution and Functional Trajectory of Sir1 in Gene Silencing. Mol Cell Biol 36:1164-79
McCleary, David F; Steakley, David Lee; Rine, Jasper (2016) Sir protein-independent repair of dicentric chromosomes in Saccharomyces cerevisiae. Mol Biol Cell 27:2879-83
Liu, Tzu-Yu; Dodson, Anne E; Terhorst, Jonathan et al. (2016) Riches of phenotype computationally extracted from microbial colonies. Proc Natl Acad Sci U S A 113:E2822-31
Steakley, David Lee; Rine, Jasper (2015) On the Mechanism of Gene Silencing in Saccharomyces cerevisiae. G3 (Bethesda) 5:1751-63

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