HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Google Scholar Articles by Harms, K. Articles by Wackernagel, W. PubMed PubMed Citation Articles by Harms, K. Articles by Wackernagel, W. Agricola Articles by Harms, K. Articles by Wackernagel, W.

The RecBCD and SbcCD DNases suppress homology-facilitated illegitimate recombination during natural transformation of Acinetobacter baylyi

Genetics, Institute of Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg, Germany

Correspondence
Wilfried Wackernagel
wilfried.wackernagel{at}uni-oldenburg.de

During natural transformation of Acinetobacter baylyi, the genomic integration of foreign (non-homologous) DNA is possible when the DNA contains a single segment homologous to the recipient genome (anchor) through homologous recombination in the anchor facilitating illegitimate recombination in the neighbouring foreign DNA (homology-facilitated illegitimate recombination; HFIR). DNA integration by HFIR occurs about 10 000 times less frequently than fully homologous recombination, but at least 100 000-fold more frequently than integration in the absence of any homology. We investigated the influence of the RecBCD enzyme (DNase/helicase) and SbcCD DNase (DNA-structure-specific single-strand endonuclease and exonuclease) on HFIR. In a recBCD null mutant the acquisition of foreign DNA was elevated 11-fold relative to wild-type cells by a 6.9-fold increased HFIR frequency and by the integration of longer stretches of foreign DNA in each event. In an sbcCD null mutant, the foreign DNA acquisition was 4.5-fold higher than in the wild-type, while homologous transformation with large DNA molecules was unaffected and increased 3.2-fold with small DNA fragments. The sbcCD mutation partially suppressed the high UV sensitivity and low viability of the recBCD mutant and also decreased its foreign DNA acquisition by HFIR to the lower level of the sbcCD mutant. We propose that suppression of HFIR results from the elimination of double-stranded intermediates of the HFIR process during transformation by RecBCD, and by SbcCD interfering with branched molecules. Our results provide evidence that the homologous recombination enzymes RecBCD and SbcCD control the level of foreign DNA acquisition by HFIR.

This article has been cited by other articles:

				N. Hulter and W. Wackernagel Frequent integration of short homologous DNA tracks during Acinetobacter baylyi transformation and influence of transcription and RecJ and SbcCD DNases Microbiology, December 1, 2008; 154(12): 3676 - 3685. [Abstract] [Full Text] [PDF]