Investigating genome instability and retrotransposition during replicative aging In Saccharomyces cerevisiae
Authors
Patterson, Melissa N.
Issue Date
2015-08
Type
Electronic thesis
Thesis
Thesis
Language
ENG
Keywords
Biology
Alternative Title
Abstract
Although we did not see an age-related effect for mutation frequency, we were able to demonstrate that S. cerevisiae Ty1 retrotransposon mobility was elevated above predicted values in replicatively aged cells and that these insertions occurred preferentially in mother cells compared to daughters. This increase in retrotransposition was correlated with significantly higher levels of Ty1 cDNA in mother cells compared with daughters. Ty1 cDNA can be mutagenic by insertion into the genome or by being used inappropriately for repair of DNA damage. Interestingly, mother cells with new insertions had a corresponding increase in gross chromosomal rearrangements compared to daughters with insertions. GCRs were particularly high in mother cells that contained tandem arrays of Ty1 elements. Normally, Ty1 inserts into genes transcribed by RNA polymerase III with the majority of inserts going to the region upstream of tRNA genes, where effect on gene function is minimal. In replicatively aged mother cells, insertion into this preferred region was significantly reduced. There was a corresponding increase in insertions into the rDNA where insertions normally occur at very low levels, potentially contributing to the increase in instability seen in this region in old yeasts cells. Further work could identify the mechanisms responsible for and the ramifications of increased retrotransposon-related genome instability during aging. Since retrotransposon regulation and consequences are very similar between yeast and mammals, future work could identify mechanisms that could be targeted to improve health and lifespan in humans.
Description
August 2015
School of Science
School of Science
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY