Identifier

etd-04082008-125746

Degree

Master of Science (MS)

Department

Biological Sciences

Document Type

Thesis

Abstract

The genes encoding the putative nuclease RecD and the helicase RecQ were deleted from Deinococcus radiodurans R1 and replaced with constructs conferring hygromycin or spectinomycin resistance. The ÄrecD and ÄrecQ strains were found to be similar to wild type R1 strain in resistance to gamma irradiation. In contrast to the single mutant strains, the ÄuvrD, ÄrecQ double mutant was found to be extremely radiation sensitive, indicating that these proteins share a complementary activity needed for radioresistance. ÄrecD mutants have higher transformation efficiencies than the wild type R1 strains, suggesting an association of RecD with nucleases that degrade single stranded DNA. Mitomycin C and ultraviolet light, DNA damaging agents that generate different patterns of DNA damage relative to ionizing radiation, were also used to induce damage in the wild type strain mutant strains. The ÄuvrD, ÄrecQ double mutant exhibited the highest sensitivity to these mutagens, reiterating that RecQ and UvrD have overlapping activities. Hydrogen peroxide increased the sensitivity of the RecQ mutant approximately ten fold, suggesting that RecFOR protein complex may be important in repairing damage mediated by oxygen radicals.

Date

2007

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

John R Battista

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