The single-polypeptide RNA polymerase of the T7 bacteriophage has been a model system for studying fundamental mechanisms of transcription ever since it was first identified almost 4 decades ago. Work over the past 15 years has revealed that the functions of this RNA polymerase extend beyond transcription of the phage genes, and that homologues of T7 RNA polymerase are widespread, occurring not only in eukaryotic mitochondria but also in mammalian nuclei, where they form the 4th major class of nuclear RNAPs (spRNAPIV). However, when compared to our detailed understanding of the structure and transcriptional mechanisms of T7RNAP, our understanding of the extra-transcriptional functions of this enzyme or of the mechanisms and biology of its mitochondrial and nuclear homologues is limited. To address these gaps in understanding we will: (1) Define the role of T7RNAP and its regulator T7 lysozyme in recruitment and assembly of the T7 DNA packaging machinery and, using both ensemble and single molecule experiments, describe the molecular details of the T7 DNA packaging reaction , (2) Determine crystal structures of yeast mitochondrial RNAP elongation and initiation complexes, and characterize the mechanism of promoter recognition by this RNA polymerase and of its activation by the mitochondrial transcription factor, (3) Identify the genes regulated by nuclear spRNAPIV and the effects of activation of respiration or of catabolite repression on spRNAPIV activity. These studies will advance our understanding of fundamental mechanisms of macromolecular complex assembly and of transcription processes in the mitochondrial and nuclear compartments of eukaryotic cells.

Public Health Relevance

RNA polymerases are the central players in the expression of genetic information. Aberrant activity of RNA polymerases leads to human disease. Our work will increase our understanding of how RNA polymerases control genes that are turned on in cancer cells and genes that are involved in cellular carbohydrate and energy metabolism, processes important in aging and diabetes.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM052522-17
Application #
8204612
Study Section
Molecular Genetics A Study Section (MGA)
Program Officer
Sledjeski, Darren D
Project Start
1995-09-30
Project End
2014-05-31
Budget Start
2011-12-01
Budget End
2014-05-31
Support Year
17
Fiscal Year
2012
Total Cost
$298,368
Indirect Cost
$97,447
Name
University of Texas Health Science Center San Antonio
Department
Biochemistry
Type
Schools of Medicine
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
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