Most eukaryotic cells contain mitochondria, the organelles required to produce cellular energy. In addition to the nuclear genome, mitochondria contain DNA and the maintenance of the mitochondrial genome is essential to the normal function of the cell. Mutations in mitochondrial DNA are associated with several human neuromuscular diseases, with age-related illnesses, such as diabetes mellitus, and with the aging process itself. The long-term goal of this project is to identify factors that are involved in the replication and repair of mitochondrial DNA using Saccharomyces cerevisiae as a model system. Mutants will be generated that increase the instability of mitochondrial microsatellite sequences. Microsatellites are regions in which a single base, or a small number of bases is repeated multiple times. Such simple repetitive sequences are abundant in eukaryotic genomes and are sensitive indicators of genomic stability because they alter at a much higher rate than non-repetitive sequences. Another approach is to determine the effect of mutations in genes whose products are known, or suspected, to be involved in DNA replication and repair in the mitochondrial compartment. In addition, studies will address the properties of the DNA sequences that affect their stable maintenance in the mitochondrial genome. The study of genes, whose products affect the stability of microsatellite sequences in the nucleus of yeast, led to the identification of the human homologs of some of these genes. Mutations in these human genes have been found to be involved in the predisposition to cancer. The experiments in this proposal are aimed at understanding the processes of mutagenesis and repair of mitochondrial DNA in yeast, however, these studies may lead to insights into similar processes in human mitochondrial DNA.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM063626-05
Application #
6926203
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Portnoy, Matthew
Project Start
2001-08-01
Project End
2007-07-31
Budget Start
2005-08-01
Budget End
2007-07-31
Support Year
5
Fiscal Year
2005
Total Cost
$263,175
Indirect Cost
Name
University of Rochester
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Pogorzala, Leah; Mookerjee, Shona; Sia, Elaine A (2009) Evidence that msh1p plays multiple roles in mitochondrial base excision repair. Genetics 182:699-709
Kalifa, Lidza; Sia, Elaine A (2007) Analysis of Rev1p and Pol zeta in mitochondrial mutagenesis suggests an alternative pathway of damage tolerance. DNA Repair (Amst) 6:1732-9
Mookerjee, Shona A; Sia, Elaine A (2006) Overlapping contributions of Msh1p and putative recombination proteins Cce1p, Din7p, and Mhr1p in large-scale recombination and genome sorting events in the mitochondrial genome of Saccharomyces cerevisiae. Mutat Res 595:91-106
Phadnis, Naina; Mehta, Reema; Meednu, Nida et al. (2006) Ntg1p, the base excision repair protein, generates mutagenic intermediates in yeast mitochondrial DNA. DNA Repair (Amst) 5:829-39
Mookerjee, Shona A; Lyon, Hiram D; Sia, Elaine A (2005) Analysis of the functional domains of the mismatch repair homologue Msh1p and its role in mitochondrial genome maintenance. Curr Genet 47:84-99
Phadnis, Naina; Sia, Rey A; Sia, Elaine A (2005) Analysis of repeat-mediated deletions in the mitochondrial genome of Saccharomyces cerevisiae. Genetics 171:1549-59
Sia, Elaine A; Kirkpatrick, David T (2005) The yeast MSH1 gene is not involved in DNA repair or recombination during meiosis. DNA Repair (Amst) 4:253-61
Phadnis, Naina; Ayres Sia, Elaine (2004) Role of the putative structural protein Sed1p in mitochondrial genome maintenance. J Mol Biol 342:1115-29
Sia, Rey A L; Urbonas, Beth L; Sia, Elaine Ayres (2003) Effects of ploidy, growth conditions and the mitochondrial nucleoid-associated protein Ilv5p on the rate of mutation of mitochondrial DNA in Saccharomyces cerevisiae. Curr Genet 44:26-37