Isolation of Nuclear-Coded Mitochondrial Genes in Chinese Hamster Cells

Donald, Denise (1993) Isolation of Nuclear-Coded Mitochondrial Genes in Chinese Hamster Cells. PhD thesis, University of Glasgow.

Abstract

Both mitochondia and chloroplasts contain DNA which codes for a small subset of genes involved in organelle biogenesis. The mitochondrial gene content and organisation is now known for a number of species from higher plants to insects to mammals. The diversity in the gene content of different species is relatively small and all mitochondria need products encoded in the nucleus and imported into the organelle, for their existence. The interaction between the mitochondrial and nuclear genomes is the subject of this thesis. Most work performed on characterising nuclear-coded mitochondrial gene products has utilized yeast due to their ability to survive without aerobic respiration, and as a consequence many mutant phenotypes have been isolated which have a defect in mitochondrial function. This is in contrast to the situation in mammalian systems, where nuclear mutations in mitochondrial respiration, unless leaky, lead to a lethal phenotype. However, some respiration-deficient mutants have been isolated from Chinese hamster cells and three have been used in this study in an attempt to isolate and characterise the mutant nuclear genes in these cell-lines. By labelling the mitochondrial proteins with S methionine in the presence of emetine which blocks cytosolic translation, the effect of the nuclear mutation on mitochondrial protein synthesis can be assayed. I have observed by using this technique that in one of the mutant cell-lines, Gal 13, there is a reduction in the level of some of the mitochonclrially encoded polypeptides. Those polypeptides which were reduced were tentatively assigned as subunits from Complex I of the electron transfer chain. This fits in with the results from a biochemical analysis on the level of activity of Complex I in Gal 13 cells which is 5% of the normal widtype level. The same study performed with Gal 50 and Gal 73 cells shows no difference in the synthesis or accumulation of mitochondrially encoded polypeptides in these two cell-lines when compared to wildtype cells. This suggests that for Gal 50 and Gal 73 cells, unlike Gal 13 cells, the nuclear mutation is not involved in the translation of mitochondrial encoded mRNAs. (Abstract shortened by ProQuest.).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Howy Jacobs
• Keywords: Genetics
• Date of Award: 1993
• Depositing User: Enlighten Team
• Unique ID: glathesis:1993-75483
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 19:50
• Last Modified: 19 Nov 2019 19:50
• URI: https://theses.gla.ac.uk/id/eprint/75483