| Literature DB >> 20023031 |
Esther J Gaasbeek1, Jaap A Wagenaar, Magalie R Guilhabert, Jos P M van Putten, Craig T Parker, Fimme J van der Wal.
Abstract
The species Campylobacter jejuni is naturally competent for DNA uptake; nevertheless, nonnaturally transformable strains do exist. For a subset of strains we previously showed that a periplasmic DNase, encoded by dns, inhibits natural transformation in C. jejuni. In the present study, genetic factors coding for DNase activity in the absence of dns were identified. DNA arrays indicated that nonnaturally transformable dns-negative strains contain putative DNA/RNA nonspecific endonucleases encoded by CJE0566 and CJE1441 of strain RM1221. These genes are located on C. jejuni integrated elements 2 and 4. Expression of CJE0566 and CJE1441 from strain RM1221 and a homologous gene from strain 07479 in DNase-negative Escherichia coli and C. jejuni strains indicated that these genes code for DNases. Genetic transfer of the genes to a naturally transformable C. jejuni strain resulted in a decreased efficiency of natural transformation. Modeling suggests that the C. jejuni DNases belong to the Serratia nuclease family. Overall, the data indicate that the acquisition of prophage-encoded DNA/RNA nonspecific endonucleases inhibits the natural transformability of C. jejuni through hydrolysis of DNA.Entities:
Mesh：
Substances：
Year: 2009 PMID： 20023031 PMCID： PMC2812962 DOI： 10.1128/JB.00867-09
Source DB: PubMed Journal: J Bacteriol ISSN： 0021-9193 Impact factor: 3.490