Type
Text
Type
Dissertation
Advisor
Martienssen, Robert A | Sternglanz, Rolf | Spector, David | Hicks, James | Kelly, William | Bernstein, Emily.
Date
2015-08-01
Keywords
Biochemistry | Fission Yeast, RNAi
Department
Department of Molecular and Cellular Biology.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76486
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
RNA interference (RNAi) is a mechanism for post-transcriptional gene silencing by RNA slicing or translational inhibition. Studies in the fission yeast S. pombe have demonstrated that RNAi components are additionally involved in transcriptional silencing by signaling chromatin assembly into the silent heterochromatin state. Originally discovered in worms and in plants, RNAi-mediated silencing is conserved in most eukaryotes with a few exceptions, including the budding yeast S. cerevisiae. Taking advantage of this observation, I initiated a candidate gene screen to search for novel components in the RNAi machinery. I identified a putative splicing factor Rct1 as one of the genes that seems to have co-evolved with RNAi components, and demonstrated that Rct1 is required for proper processing of heterochromatic transcripts into siRNAs. My results showed that Rct1 guides heterochromatic transcripts to the RNAi machinery and prevents transcript targeting by the exosome. Surprisingly, Rct1 is dispensable for H3K9 methylation, suggesting siRNAs do not in themselves mediate heterochromatin assembly. In addition to Rct1, I identified five more genes that are specific to S. pombe, with no apparent S. cerevisiae homolog and yet are conserved in higher eukaryotes, which are required for robust heterochromatic silencing. Taken together, my study identified several potential novel RNAi factors and demonstrated that siRNA biogenesis and H3K9 methylation could be uncoupled while intact RNAi machinery is present, indicating an additional role of RNAi machinery in heterochromatin assembly. | 178 pages
Recommended Citation
Chang, An-Yun, "The Identification of Novel Components in the RNAi machinery in Fission Yeast S. pombe" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2401.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2401