Eukaryotic transcription is regulated by multiprotein-complexes, known as coactivators, which alter chromatin or recruit general transcription factors to facilitate gene expression. Most promoters studied use several coactivators for normal transcriptional regulation. Interestingly, some results suggest that coactivator complexes are functionally redundant in vivo, even though the complexes themselves have distinct biochemical activities. SAGA and Swi/Snf, two coactivators conserved throughout eukaryotes, have been shown to be redundant at particular genes in S. cerevisiae. SAGA has multiple activities including histone acetylation, deubiquitination, and recruitment of general transcription factors while Swi/Snf is important for nucleosome remodeling. Individually, these complexes are not essential for viability in S. cerevisiae, yet double mutants that have lost both complexes are inviable, suggesting functional redundancy. The cause of this redundancy is poorly understood. In this proposal, the role of redundancy in transcriptional regulation will be addressed through two complementary approaches, using S. cerevisiae as a model organism. First, the consequences of loss of both coactivators will be assayed, using a rapid, inducible protein-depletion system known as "AID". Use of this conditional protein depletion system will allow comparisons of changes in genome- wide transcriptional profiles and coactivator localization following depletion of complexes, either singly or together. This approach will determine which of the changes in transcriptional output underlie the double mutant lethality. Second, a screen for mutants that suppress the lethality of SAGA and Swi/Snf double mutants will be conducted. The identification and analysis of suppressor mutations will provide significant insight into the mechanism allowing these two complexes to act redundantly. Given the conserved nature of these coactivators and their roles development and diseases, including cancer, understanding the mechanism behind their redundancy remains an important but yet unexplored area of eukaryotic gene expression. !

Public Health Relevance

At every gene, multiple factors must be coordinate to ensure proper regulation. Failure do so correctly results in the inappropriate gene activity that underlie many diseases, including cancer. Through study in a model system, yeast, we aim to learn how these factors are coordinated and thus their role in disease will be better understood.!

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32GM106548-01A1
Application #
8645123
Study Section
Special Emphasis Panel (ZRG1-F08-A (20))
Program Officer
Janes, Daniel E
Project Start
2013-12-03
Project End
2015-12-02
Budget Start
2013-12-03
Budget End
2014-12-02
Support Year
1
Fiscal Year
2014
Total Cost
$52,190
Indirect Cost
Name
Harvard University
Department
Genetics
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115