Cornell University
Library
Cornell UniversityLibrary

eCommons

Help
Log In(current)
  1. Home
  2. Cornell University Graduate School
  3. Cornell Theses and Dissertations
  4. The Conserved Pch2 Gene Acts To Regulate Dna Doublestrand Break Repair In Saccharomyces Cerevisiae Meiosis

The Conserved Pch2 Gene Acts To Regulate Dna Doublestrand Break Repair In Saccharomyces Cerevisiae Meiosis

File(s)
Zanders, Sarah.pdf (102.43 MB)
Permanent Link(s)
https://hdl.handle.net/1813/17630
Collections
Cornell Theses and Dissertations
Author
Zanders, Sarah
Abstract

In the first chromosome division of meiosis (MI), homologous chromosome pairs are separated, allowing for the production of fertile haploid gametes from diploid progenitor cells. Proper MI segregation of homologous chromosomes in most eukaryotic organisms requires that at least one programmed DNA double-strand break (DSB) per pair of homologous chromosomes is repaired as a crossover. These crossover events tether homologous chromosomes together, which allows for the generation of a bipolar spindle to separate the homologous chromosomes. The widely conserved PCH2 gene of Saccharomyces cerevisiae is involved in regulating the repair of meiotic DSBs. First, Pch2 promotes the use of the homologous chromosome, instead of the sister chromatid, as a DSB repair template. Second, Pch2 regulates the fate of DSBs that are repaired using the homologous chromosome by limiting gene conversion and by promoting crossover interference. pch2 mutants repair a greater proportion of meiotic DSBs using the sister chromatid than wild-type cells, but the majority of DSBs are still repaired using the homologous chromosome. The DSBs that are repaired using the homologous chromosome in pch2 mutants have a higher likelihood to be associated with gene conversion events and to be repaired as crossovers, as opposed to noncrossovers. The distribution of crossover events observed in pch2 also demonstrates a significant reduction in crossover interference in these mutants. I hypothesize that a single Pch2-dependent role in meiotic chromosome axis organization inhibits intersister DSB repair, limits gene conversion tract length, and promotes the interference regulation of interhomolog DSB repair.

Date Issued
2010-10-20
Type
dissertation or thesis

Site Statistics | Help

About eCommons | Policies | Terms of use | Contact Us

copyright © 2002-2026 Cornell University Library | Privacy | Web Accessibility Assistance