Authors
Bryll, Alysia RFaculty Advisor
Craig PetersonAcademic Program
MD/PhDUMass Chan Affiliations
Program of Molecular MedicineDocument Type
Doctoral DissertationPublication Date
2022-04-13Keywords
Transcriptional HomeostasisRNA exosome
H2A.Z
Hst3
H3K56Ac
Chromatin
SIRT6
Histone deacetylase
Biochemistry, Biophysics, and Structural Biology
Metadata
Show full item recordAbstract
Multiple regulatory mechanisms work to ensure that eukaryotic transcription maintains mRNA pools and subsequent protein synthesis. When errors in transcription occur, deleterious effects on cellular fitness can develop. RNA degradation as well as histone modifications, specifically at promoter proximal nucleosomes, play a critical role in maintaining transcription, but, exact mechanisms are not fully understood. In this dissertation, I investigate the role of RNA degradation and chromatin dynamics in transcription regulation as well as further understand, through biochemical analysis, a critical histone deacetylase. Using various genome-wide methodologies in Saccharomyces cerevisiae, we find a functional interaction between the nuclear RNA exosome and histone variant H2A.Z that maintains mRNA levels. There is a reduction in RNA polymerase II nascent transcription following RNA exosome subunit Rrp6 depletion that is further globally accentuated with H2A.Z deposition loss. To understand the mechanism leading to this global reduction, we identify the mRNA of Sirtuin histone deacetylase Hst3 as a target of the RNA exosome, revealing a means to link degradation to the transcription machinery. These findings show that even slight changes in deacetylase or acetylase activity can have significant effects on transcription. Additionally, we reveal a global impact of H2A.Z on transcription. We further investigate the functional and structural significance of human surtuin histone deacetylase SIRT6 (yeast homolog Hst3). Using histone deacetylase assays, we confirm the significance of specific residues of SIRT6 in nucleosome binding and deacetylase activity. Additionally, we show SIRT6 has reduced deacetylase activity in vitro on acetylated lysine 56 as compared to acetylated lysine 9 on histone H3. Finally, we confirm structural findings that the histone tail of H2A impacts SIRT6 H3K9Ac deacetylation activity. Together, these findings indicate a critical importance of histone deacetylase activity in maintaining transcription, a novel role of H2A.Z in global transcription regulation that furthers our understanding of SIRT6 structure and function.DOI
10.13028/st3h-t221Permanent Link to this Item
http://hdl.handle.net/20.500.14038/32391Rights
Copyright is held by the author, with all rights reserved.ae974a485f413a2113503eed53cd6c53
10.13028/st3h-t221