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Characterization of Rkr1, a nuclear, RING-domain protein with functional connections to chromatin modification in Saccharomyces cerevisiae

Braun, Mary A (2007) Characterization of Rkr1, a nuclear, RING-domain protein with functional connections to chromatin modification in Saccharomyces cerevisiae. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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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.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Braun, Mary Amab259@pitt.eduMAB259
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairArndt, Karen M.arndt@pitt.eduARNDT
Committee MemberOke, C. Valerie
Committee MemberLawrence, Jeffrey G.
Committee MemberBrodsky, Jeffrey L.
Committee MemberWoolford, John L.
Date: 19 September 2007
Date Type: Completion
Defense Date: 30 May 2007
Approval Date: 19 September 2007
Submission Date: 28 June 2007
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Biological Sciences
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: chromatin; histone modification; Rtf1; transcription; Paf1 complex; telomeric silencing
Other ID:, etd-06282007-120141
Date Deposited: 10 Nov 2011 19:48
Last Modified: 15 Nov 2016 13:45


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