Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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Author: search.filters.author.polansky, steven carl

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    EXPRESSING DEINOCOCCUS RADIODURANS RECD IN ESCHERICHIA COLI: PHENOTYPIC EFFECTS IN RECBCD(-) AND RECD(-) CELLS
    (2006-12-20) polansky, steven carl; Julin, Douglas A; Biochemistry; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The RecD helicase is a member of the RecBCD complex, which is essential for repair of double-stranded breaks (DSBs) in DNA via homologous recombination in Escherichia coli. The microbe Deinococcus radiodurans is capable of fixing high amounts of DSBs, owing to an efficient repair system. However, Deinococcus does not contain any recB or recC genes; only a RecD-like helicase has been observed. In Escherichia coli strains mutant for the native RecD subunit, the D. radiodurans RecD cannot restore nuclease activity when infected with T4 gene2- bacteriophage. Cell viability tests and mitomycin C exposure of RecBC(+)D(-) strains show no adverse effects from the Dr RecD. A negative phenotype was encountered with strains lacking RecBCD and expressing D. radiodurans RecD protein. Microscopy studies of RecBCD(-) E. coli expressing the D. radiodurans RecD helicase show long cellular structures termed filaments. The Dr RecD protein may be binding to and disrupting the replication fork.