RNA Polymerase II (Pol II) transcription is a highly regulated process. Many factors associate with Pol II to ensure that transcription occurs as efficiently as possible. One of these factors is the Paf1 complex, which consists of the subunits Paf1, Ctr9, Rtf1, Cdc73, and Leo1. This complex has been shown to be important for the regulation of chromatin modifications that promote active transcription. Rkr1 was identified in a genetic screen to uncover factors that function in parallel with the Paf1 subunit Rtf1. My work has focused on characterizing a role for Rkr1 in transcription and chromatin function. I have shown that strains lacking RKR1 have transcription-related phenotypes. Genetic analysis has shown that Rkr1 functions in parallel with Rtf1-dependent histone modifications, particularly histone H2B ubiquitylation and histone H3 lysine 4 methylation. Strains lacking RKR1 have telomeric silencing defects, further connecting Rkr1 to chromatin function. Rkr1 is a nuclear protein that contains a RING domain at its extreme carboxy terminus. RING domain proteins often act as ubiquitin-protein ligases, which determine substrate specificity in the ubiquitylation pathway. Subsequent analyses have shown that Rkr1 does possess ubiquitin ligase activity in vitro, and mutational analysis shows that the RING domain of Rkr1 is required for in vivo activity. In an attempt to identify a functional process for Rkr1, a yeast two-hybrid screen was performed using an amino-terminal fragment of Rkr1 as bait. Twenty proteins were identified to interact with this region of Rkr1, many of which are functionally connected to transcription and chromatin. Microarray analysis shows that Rkr1 is required for proper expression of a subset of genes in yeast. Taken together, my work has identified a new ubiquitylation pathway within the nucleus that acts to regulate transcription and chromatin function.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-06282007-120141 |
| Date | 19 September 2007 |
| Creators | Braun, Mary A |
| Contributors | John L. Woolford, C. Valerie Oke, Karen M. Arndt, Jeffrey L. Brodsky, Jeffrey G. Lawrence |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-06282007-120141/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.0158 seconds