Date

10-26-2010

UMMS Affiliation

Graduate School of Biomedical Sciences, Program in Biochemistry and Molecular Pharmacology

Document Type

Dissertation, Doctoral

Subjects

Positive Transcriptional Elongation Factor B; RNA Polymerase II; Transcription Factors; HIV-1; Dissertations, UMMS

Disciplines

Genetics and Genomics | Life Sciences | Medicine and Health Sciences

Abstract


RNA polymerase II-mediated transcription of HIV-1 genes depends on positive transcription elongation factor b (P-TEFb), the complex of cyclin T1 and CDK9. Recent evidence suggests that regulation of transcription by P-TEFb involves chromatin binding and modifying factors. To determine how P-TEFb may connect chromatin remodeling to transcription, we investigated the relationship between P-TEFb and histone H1. We show that P-TEFb interacts with H1 and that H1 phosphorylation in cell culture correlates with P-TEFb activity. Importantly, P-TEFb also directs H1 phosphorylation during Tat transactivation and wild type HIV-1 infection. Our results also show that P-TEFb phosphorylates histone H1.1 at a specific C-terminal site. Expression of a mutant H1.1 that cannot be phosphorylated by P-TEFb disrupts Tat transactivation as well as transcription of the c-fos and hsp70 genes in HeLa cells. P-TEFb phosphorylation of H1 also plays a role in the expression of muscle differentiation marker genes in the skeletal myoblast cell line C2C12. Additionally, ChIP experiments demonstrate that H1 dissociates from the HIV-1 LTR in MAGI cells, stress-activated genes in HeLa cells, and muscle differentiation marker genes in C2C12 cells under active P-TEFb conditions. Our results overall suggest a new role for P-TEFb in both cellular and HIV-1 transcription through chromatin.

Rights and Permissions

Copyright is held by the author, with all rights reserved.

 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.