The long-range goals of this laboratory are to analyse at both the molecular and cellular levels the mutation, evolution, transmission, segregation and recombination of mtDNA in mammalian cells and the role of mitochondrial genes in cellular energy production and intermediary metabolism. These studies relate to many areas of health science, particularly cancer biology. The principal aim during the next period of support will be to analyze the mitochondrial mutants isolated in this laboratory at the molecular level using the techniques of somatic cell genetics and DNA biochemistry. Specific projects include: a) The series of mitochondrial cytochrome b mutants will be used for sequencing studies to determine the mtDNA alterations encoding the different phenotypes. b) Wild type mutant cell lines expressing the CAP-R, PYR-IND and OLI-R mitochondrial phenotypes will be used for sequencing studies to determine whether all three phenotypes are encoded by a single or multiple mtDNA mutational events and the map positions of the sequence changes in the mitochondrial large ribosomal RNA gene. c) The mechanism of mtDNA segregation will be analyzed using both physical and genetic mtDNA markers. The genetic control of the frequencies of the PYR-IND and OLI-R phenotypes will also be analysed in a series of cybrid crosses. d) The actual mtDNA mutation frequency of an established cell line will be determined by cloning and analysing a series of mtDNA molecules.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM033683-03
Application #
3283580
Study Section
Molecular Biology Study Section (MBY)
Project Start
1984-01-01
Project End
1988-02-29
Budget Start
1986-01-01
Budget End
1988-02-29
Support Year
3
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Type
Schools of Medicine
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555
Howell, N; Kubacka, I; Smith, R et al. (1996) Association of the mitochondrial 8344 MERRF mutation with maternally inherited spinocerebellar degeneration and Leigh disease. Neurology 46:219-22
Howell, N; Kubacka, I; Halvorson, S et al. (1995) Phylogenetic analysis of the mitochondrial genomes from Leber hereditary optic neuropathy pedigrees. Genetics 140:285-302
Howell, N; Kubacka, I (1993) Sequence analysis of mitochondrial chloramphenicol resistance mutations in Chinese hamster cells. Mamm Genome 4:271-5
Howell, N; Robertson, D E (1993) Electrochemical and spectral analysis of the long-range interactions between the Qo and Qi sites and the heme prosthetic groups in ubiquinol-cytochrome c oxidoreductase. Biochemistry 32:11162-72
Howell, N; Kubacka, I; Xu, M et al. (1991) Leber hereditary optic neuropathy: involvement of the mitochondrial ND1 gene and evidence for an intragenic suppressor mutation. Am J Hum Genet 48:935-42
Howell, N; McCullough, D (1990) An example of Leber hereditary optic neuropathy not involving a mutation in the mitochondrial ND4 gene. Am J Hum Genet 47:629-34
Howell, N (1990) Glycine-231 residue of the mouse mitochondrial protonmotive cytochrome b: mutation to aspartic acid deranges electron transport. Biochemistry 29:8970-7
Raag, R; Poulos, T L (1989) The structural basis for substrate-induced changes in redox potential and spin equilibrium in cytochrome P-450CAM. Biochemistry 28:917-22
Howell, N (1989) Evolutionary conservation of protein regions in the protonmotive cytochrome b and their possible roles in redox catalysis. J Mol Evol 29:157-69
Howell, N; Lee, A (1989) Sequence analysis of mouse mitochondrial chloramphenicol-resistant mutants. Somat Cell Mol Genet 15:237-44

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