Structural Inheritance in Yeast
Final rept. 1 Jul 2003-30 Jun 2006
SEATTLE UNIV WA
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We previously identified an example of structural inheritance whereby yeast mitochondria can exist in two alternative states thereby conferring two different sets of growth properties. In the Leu state, rhozero yeast grow at rates indistinguishable from their mitochondrial DNA-containing rhoplus parent while LeuP rhozero cells exhibit slow growth and partial leucine auxotrophy. We have made progress in elucidating the difference between Leu and LeuP strains and have also searched for additional examples of structural inheritance in yeast. Nfu1p is a mitochondrial protein that is involved in both FeS complex formation and mitochondrial chaperones, two functions that are consistent with their participation with LeuP. Relative to wild type strains, nfu1 strains show a substantially higher fraction of rhozero derivatives that are LeuP. These nfu1 LeuP rhozero strains also show a greater frequency of conversion to Leu. New examples of structural inheritance were sought by examining the peroxisome and the vacuole, two potentially non-essential organelles. Using an unlinked non-complementation approach modified to uncover evidence of structural templating, we have been unable to find evidence to support the idea that either of these organelles provides an essential seed for the generation of additional copies of these structures. Our current efforts to find new examples of structural inheritance are leading us to examine other multi-subunit enzymes, such as the respiratory complexes, that might harbor structural information. Our studies of peroxisome biogenesis, while unfruitful as far as structural inheritance is concerned, have led to the surprising discovery that beta-oxidation is required to prevent the toxicity of fatty acids.
- Anatomy and Physiology
- Medicine and Medical Research