Type
Text
Type
Dissertation
Advisor
Leatherwood, Janet | Futcher, Bruce | Neiman, Aaron | Karzai, Wali | Hoffman, Charles.
Date
2015-05-01
Keywords
exosome, Mei2, Mmi1, pombe, RNA, Rrp6 | Genetics
Department
Department of Genetics.
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/11401/77617
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
The fission yeast Schizosaccharomyces pombe grows by mitotic divisions as a haploid when nutrition is adequate. When starved for nitrogen, it mates with a cell of opposite mating type, undergoes meiosis and forms spores. When S. pombe cells switch from mitosis to meiosis, there is a massive rewiring of gene expression, controlled by both transcriptional and post-transcriptional gene regulation. I have studied two major post-transcriptional gene regulatory mechanisms during early meiosis in S. pombe. A subset of early meiotic genes are actively transcribed even during vegetative growth, but an RNA binding protein called Mmi1 binds to their RNA and targets the RNA for degradation. We previously showed that two exonucleases of the exosome, Rrp6 and Dis3, are involved in degrading early meiotic RNAs. In my first project, I discovered that Rrp6 plays a structural role in targeting early meiotic RNAs to the exosome. This function is very important for meiotic gene regulation even when Rrp6 itself lacks exonuclease activity to degrade RNAs. Unexpectedly, genome-wide analysis revealed that Rrp6 also targeted a subset of iron homeostasis mRNAs to the exosome, when sufficient iron was present. These mRNAs shared a nucleotide motif, indicating that they were possible targets of an unidentified RNA binding protein. Induction of the early meiotic genes requires a specific RNA binding protein, Mei2. Mei2 is the master regulator of meiotic initiation in S. pombe, but the early steps controlled by Mei2 are unknown. In the next part of my dissertation research, I determined the RNAs bound to Mei2. Cells lacking Mei2 RNA binding activity cannot initiate meiosis. The only known partner of Mei2 is a noncoding RNA called meiRNA. However, Mei2 can trigger early meiotic events even in cells lacking meiRNA. This suggests that Mei2 must have additional RNA partners, which I aimed to determine in a genome-wide study. I found that Mei2 binds to the 5’ UTR of two key meiotic inhibitors, mmi1 and rep2. These results led to a model for meiotic induction by Mei2 and the hypothesis that initial meiotic induction by Mei2 is accomplished by down-regulating mmi1 and rep2. | The fission yeast Schizosaccharomyces pombe grows by mitotic divisions as a haploid when nutrition is adequate. When starved for nitrogen, it mates with a cell of opposite mating type, undergoes meiosis and forms spores. When S. pombe cells switch from mitosis to meiosis, there is a massive rewiring of gene expression, controlled by both transcriptional and post-transcriptional gene regulation. I have studied two major post-transcriptional gene regulatory mechanisms during early meiosis in S. pombe. A subset of early meiotic genes are actively transcribed even during vegetative growth, but an RNA binding protein called Mmi1 binds to their RNA and targets the RNA for degradation. We previously showed that two exonucleases of the exosome, Rrp6 and Dis3, are involved in degrading early meiotic RNAs. In my first project, I discovered that Rrp6 plays a structural role in targeting early meiotic RNAs to the exosome. This function is very important for meiotic gene regulation even when Rrp6 itself lacks exonuclease activity to degrade RNAs. Unexpectedly, genome-wide analysis revealed that Rrp6 also targeted a subset of iron homeostasis mRNAs to the exosome, when sufficient iron was present. These mRNAs shared a nucleotide motif, indicating that they were possible targets of an unidentified RNA binding protein. Induction of the early meiotic genes requires a specific RNA binding protein, Mei2. Mei2 is the master regulator of meiotic initiation in S. pombe, but the early steps controlled by Mei2 are unknown. In the next part of my dissertation research, I determined the RNAs bound to Mei2. Cells lacking Mei2 RNA binding activity cannot initiate meiosis. The only known partner of Mei2 is a noncoding RNA called meiRNA. However, Mei2 can trigger early meiotic events even in cells lacking meiRNA. This suggests that Mei2 must have additional RNA partners, which I aimed to determine in a genome-wide study. I found that Mei2 binds to the 5’ UTR of two key meiotic inhibitors, mmi1 and rep2. These results led to a model for meiotic induction by Mei2 and the hypothesis that initial meiotic induction by Mei2 is accomplished by down-regulating mmi1 and rep2. | 125 pages
Recommended Citation
Mukherjee, Kaustav, "Post-transcriptional Gene Regulation During Meiosis in Schizosaccharomyces pombe" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3412.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3412