The <I>Saccharomyces cerevisiae</I> checkpoint genes <I>RAD9, RAD17, RAD24</I>, and <I>MEC3</I> are required for the transcriptional induction of a group of genes including some for DNA repair. In this thesis two of the checkpoint genes, <I>RAD9</I> and <I>RAD24</I>, and two nucleotide excision repair (NER) genes <I>RAD16</I> and <I>RAD26</I>, have been investigated for their role in inducible NER at the <I>MFA2</I> gene at nucleotide resolution. In wild type cells, enhanced NER is detected in cells received a minor UV irradiation one hour prior to a main UV dose compared to cells only treated with the main UV dose. This inducible NER is not detectable in mutant strains <I>rad9, rad24, rad9rad24, rad16</I> and <I>rad26</I>. These data suggest that inducible NER is dependent on the checkpoint genes <I>RAD9 </I>and <I>RAD24</I>, on the <I>RAD16</I> gene that is essential for global genome repair (GGR), and on the <I>RAD26 </I>gene that is required for efficient transcription-coupled repair (TCR). A second aspect of the thesis examined the role of histone acetylation in NER. Histone acetyltransferases (HATs) play an important role in remodelling chromatin structure during transcription activation. Here, the role of one HAT, Gen5, in the NER of UV induced CPDs in the upstream region of <I>MFA2 </I>has been examined. In Δ<I>gcn5</I> strains, NER of both strands in the control region of <I>MFA2</I> is slower than in wild type cells. As Gen5 regulates <I>MFA2</I> transcription, probably through chromatin modification, its role in chromatin organization in the control region of <I>MFA2</I> would appear to influence DNA repair in that region.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:636719 |
| Date | January 2001 |
| Creators | Yu, S. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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