Thesis
Cellular response of the hyperthermophilic archaeon Sulfolobus solfataricus to radiation damage
Washington State University
Master of Science (MS), Washington State University
2009
Handle:
https://hdl.handle.net/2376/101580
Abstract
DNA repair pathways in archaea such as Sulfolobus species have long been a source of interest due to natural environments in which they are exposed to high temperatures, acidic pH, and solar radiation. Despite harsh conditions that likely lead to constant DNA damage, these organisms have similar mutation rates to mesophilic species such as E. coli and thus are hypothesized to have efficient methods of repairing DNA damage. Here, the response of Sulfolobus solfataricus to ultraviolet (UV) and ionizing radiation is investigated. The recovery of S. solfataricus to both forms of radiation was found to be strain specific. Investigation of genes involved in the S. solfataricus homologous recombination (HR) pathway revealed upregulation of radA and rad54 transcripts following UV and ionizing radiation. Further examination of the rad54 gene locus elucidated strain specific differences in this gene, and western hybridization analysis only detected a protein product in the strain containing the undisrupted gene. This is the first report of strain specific differences in the S. solfataricus response to damage, the first detailed report of increased transcript abundance of genes involved in HR following UV radiation, and the first characterization of SsoRad54 in vivo. Our findings about the S. solfataricus damage response are consistent with the precedent of this organism as a model archaeon for studying complex eukaryotic processes such as DNA repair. To gain a better understanding of double-strand break repair mechanisms in archaea, the S. solfataricus genome was searched for evidence of an end-joining pathway. An uncharacterized open reading frame was identified as a putative S. solfataricus Ku gene. Transcription of this gene was found to be upregulated in response to UV and ionizing radiation, indicating potential involvement in DNA repair. Finally, S. solfataricus whole cell extracts were assessed for end-joining activity and found to consistently ligate linear DNA substrates. Together, these results implicate a previously uncharacterized end-joining pathway in S. solfataricus.
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Details
- Title
- Cellular response of the hyperthermophilic archaeon Sulfolobus solfataricus to radiation damage
- Creators
- Marian Frances Laughery
- Contributors
- Cynthia A. Haseltine (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Molecular Biosciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525026101842
- Language
- English
- Resource Type
- Thesis