Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

UNCOVERING THE MECHANISM OF CHROMATIN ASSOCIATION OF THE PAF1 TRANSCRIPTION ELONGATION COMPLEX

Mayekar, Manasi (2013) UNCOVERING THE MECHANISM OF CHROMATIN ASSOCIATION OF THE PAF1 TRANSCRIPTION ELONGATION COMPLEX. Doctoral Dissertation, University of Pittsburgh.

This is the latest version of this item.

[img]
Preview
PDF
Primary Text

Download (4MB) | Preview

Abstract

Paf1C co-localizes with Pol II and influences gene expression by regulating transcription initiation, elongation and termination. Some crucial functions of Paf1C include promoting co-transcriptional histone modifications and recruiting termination factors. The mechanism of chromatin recruitment of Paf1C was obscure. We identified the importance of a conserved region within the Rtf1 subunit of Paf1C, termed the ORF association region (OAR), in chromatin-tethering of Paf1C. I found that the interaction of Paf1C with the transcription elongation factor Spt5 was mediated by the Rtf1 OAR and the Spt5 C-terminal region (CTR). Binding assays established the direct nature of the Rtf1-Spt5 interaction and the sufficiency of the Rtf1 OAR and the Spt5 CTR for this interaction. ChIP assays demonstrated the ability of the OAR to mimic the chromatin association pattern of Paf1C, independent of Paf1C but dependent on the Spt5 CTR and the Bur1 kinase. This suggests that the targeting of the OAR tethers Paf1C to chromatin. Collectively, these results provide a molecular mechanism for coupling Paf1C with the transcription machinery.
Additionally, I found that substitution of OAR residues predicted to be important for the human Rtf1 OAR-Spt5 CTR interaction in the OAR-CTR co-crystal impaired the chromatin association of Paf1C supporting the relevance of the co-crystal interactions. Furthermore, I showed that strains that are doubly mutated in the OAR and the Cdc73 C-domain exhibited cumulative reduction in Paf1C chromatin occupancy. Consistently, I showed that cells lacking both the OAR and the C-domain lose Paf1C-mediated histone modifications. This indicates that the Rtf1 OAR and the Cdc73 C-domain facilitate dual-attachment of Paf1C to chromatin.
My work has also provided better understanding of the function of the histone modification domain (HMD) of Rtf1. I found that overexpression of the HMD was essential for it to promote histone modifications. Additionally, I showed that the HMD is sufficient for the H2B K123 Ub, the mark upstream of the H3 K4 and H3 K79 methylation events, but the rest of Paf1C is required for the HMD to stimulate H3 K4 Me3 modification. Cumulatively, my findings provide additional insight into the regulation of histone modifications by the Rtf1 HMD.


Share

Citation/Export:
Social Networking:
Share |

Details

Item Type: University of Pittsburgh ETD
Status: Published
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Mayekar, Manasimanasi85@gmail.com
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairArndt, Karenarndt@pitt.eduARNDT
Committee MemberSchmidt, Martinmcs2@pitt.eduMCS2
Committee MemberSchwacha, Anthonyschwacha@pitt.eduSCHWACHA
Committee MemberTsang, Michael tsang@pitt.eduTSANG
Committee MemberVanDemark, Andrew andyv@pitt.eduANDYV
Date: 18 November 2013
Date Type: Publication
Defense Date: 30 October 2013
Approval Date: 18 November 2013
Submission Date: 15 November 2013
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 208
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Biochemistry and Molecular Genetics
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Chromatin, Transcription, Paf1 complex, Histone modifications, Rtf1, Spt5
Date Deposited: 18 Nov 2013 15:29
Last Modified: 15 Nov 2016 14:15
URI: http://d-scholarship.pitt.edu/id/eprint/20010

Available Versions of this Item

  • UNCOVERING THE MECHANISM OF CHROMATIN ASSOCIATION OF THE PAF1 TRANSCRIPTION ELONGATION COMPLEX. (deposited 18 Nov 2013 15:29) [Currently Displayed]

Metrics

Monthly Views for the past 3 years

Plum Analytics


Actions (login required)

View Item View Item