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Roles of ExoI and SbcCD Nucleases in “Reckless” DNA Degradation in recA Mutants of Escherichia coli
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| Zeitschriftentitel: | Journal of Bacteriology |
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| Personen und Körperschaften: | , , , |
| In: | Journal of Bacteriology, 191, 2009, 5, S. 1677-1687 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
American Society for Microbiology
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| Schlagwörter: |
| Zusammenfassung: | <jats:title>ABSTRACT</jats:title> <jats:p> Exponentially growing <jats:italic>recA</jats:italic> mutant cells of <jats:italic>Escherichia coli</jats:italic> display pronounced DNA degradation that starts at the sites of DNA damage and depends on RecBCD nuclease (ExoV) activity. As a consequence of this “reckless” DNA degradation, populations of <jats:italic>recA</jats:italic> mutants contain a large proportion of anucleate cells. We have found that both DNA degradation and anucleate-cell production are efficiently suppressed by mutations in the <jats:italic>xonA</jats:italic> ( <jats:italic>sbcB</jats:italic> ) and <jats:italic>sbcD</jats:italic> genes. The suppressive effects of these mutations were observed in normally grown, as well as in UV-irradiated, <jats:italic>recA</jats:italic> cells. The products of the <jats:italic>xonA</jats:italic> and <jats:italic>sbcD</jats:italic> genes are known to code for the ExoI and SbcCD nucleases, respectively. Since both <jats:italic>xonA</jats:italic> and <jats:italic>sbcD</jats:italic> mutations are required for strong suppression of DNA degradation while individual mutations have only a weak suppressive effect, we infer that ExoI and SbcCD play partially redundant roles in regulating DNA degradation in <jats:italic>recA</jats:italic> cells. We suggest that their roles might be in processing (blunting) DNA ends, thereby producing suitable substrates for RecBCD binding. </jats:p> |
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| Umfang: | 1677-1687 |
| ISSN: |
1098-5530
0021-9193 |
| DOI: | 10.1128/jb.01877-07 |