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Amplified UvrA protein can ameliorate the ultraviolet sensitivity of an Escherichia coli recA mutant.

Authors
  • Kiyosawa, K
  • Tanaka, M
  • Matsunaga, T
  • Nikaido, O
  • Yamamoto, K
Type
Published Article
Journal
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
Publisher
Elsevier
Publication Date
Dec 19, 2001
Volume
487
Issue
3-4
Pages
149–156
Identifiers
PMID: 11738941
Source
Medline
License
Unknown

Abstract

When a recA strain of Escherichia coli was transformed with the multicopy plasmid pSF11 carrying the uvrA gene of E. coli, its extreme ultraviolet (UV) sensitivity was decreased. The sensitivity of the lexA1 (Ind(-)) strain to UV was also decreased by pSF11. The recA cells expressing Neurospora crassa UV damage endonuclease (UVDE), encoding UV-endonuclease, show UV resistance. On the other hand, only partial amelioration of UV sensitivity of the recA strain was observed in the presence of the plasmid pNP10 carrying the uvrB gene. Host cell reactivation of UV-irradiated lambda phage in recA cells with pSF11 was as efficient as that in wild-type cells. Using an antibody to detect cyclobutane pyrimidine dimers, we found that UV-irradiated recA cells removed dimers from their DNA more rapidly if they carried pSF11 than if they carried a vacant control plasmid. Using anti-UvrA antibody, we observed that the expression level of UvrA protein was about 20-fold higher in the recA strain with pSF11 than in the recA strain without pSF11. Our results were consistent with the idea that constitutive level of UvrA protein in the recA cells results in constitutive levels of active UvrABC nuclease which is not enough to operate full nucleotide excision repair (NER), thus leading to extreme UV sensitivity.

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