Type
Text
Type
Dissertation
Advisor
Seeliger, Markus | Garcia-Diaz, Miguel | Bowen, Mark | Bogenhagen, Daniel.
Date
2014-12-01
Keywords
Biochemistry | MELAS, Mitochondria, Mitochondrial Disease, MTERF, POLRMT, Transcription
Department
Department of Biochemistry and Structural Biology.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76952
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Human mitochondria are found in all eukaryotic cells. They are dynamic double membrane organelles that can vary in shape, size and amount depending on cell types. In humans, mitochondria contain a 16.5 kb genome that encodes for 22 tRNAs, two rRNAs and 13 proteins that make up the mitochondrial contribution of the oxidative phosphorylation system (OXPHOS). This system produces the majority of energy used by the cell in the form of ATP and is critical for cell viability. In order for the OXPHOS system to produce ATP, it is dependent on the proper expression of the mitochondrial genome. Thus, errors in gene expression can lead to defects in OXPHOS and ultimately pathogenesis of mitochondrial disease. Therefore, it is important to understand the mechanisms of mitochondrial gene expression and how alteration of these mechanisms can result in pathogenesis. The initial stage in gene expression is transcription, a process that involves several events including initiation, elongation and termination, all of which are regulated by proteins that are produced in the nucleus and transported to the mitochondria. Interestingly, termination is one of the least understood aspects of transcription. It has been established that termination is regulated by the mitochondrial transcription termination factor MTERF1. Our lab has solved the crystal structure of MTERF1 bound to its canonical DNA sequence located within the tRNALeu gene and made great progress in understanding the mechanisms critical for MTERF1 mediated transcription termination. Most strikingly, MTERF1 exhibits a unique DNA binding mode that involves the formation of sequence specific interactions, helix unwinding and the eversion of three nucleotides stabilized by stacking interactions outside the double helix. Further structural and biochemical characterization of the base flipping mechanics has revealed a stepwise order to the base-flipping event that is important for function. In addition, we show that pathogenic mutations present within the DNA binding site perturb sequence recognition and base flipping. These result in termination defects that have implication for pathogenesis of mitochondrial disease. | 119 pages
Recommended Citation
Byrnes, James, "Alterations to the unique DNA binding mode mediated by MTERF1 have implications of pathogenesis in mitochondrial disease" (2014). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2820.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2820