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Volume 159, Issue Pt_8

Analysis of the transcriptome of mutant reveals a new mobile genetic element Free

Abstract

Hfq is a small RNA-binding protein involved in the post-transcriptional regulation of gene expression by affecting the stability of the mRNA and by mediating efficient pairing between small regulatory RNAs and their target mRNAs. In , the aetiological agent of Legionnaires’ disease, mutation of results in increased duration of the lag phase and reduced growth in low-iron medium. In an effort to uncover genes potentially regulated by Hfq, the transcriptome of an mutant strain was compared to that of the wild-type. Unexpectedly, many genes located within a 100 kb genomic island, including a section of the previously identified efflux island, were overexpressed in the mutant strain. Since this island contains a putative conjugative system and an integrase, it was postulated that it could be a new integrated mobile genetic element. PCR analysis revealed that this region exists both as an integrated and as an episomal form in the cell population and that it undergoes differential excision in the mutant background, which was further confirmed by -complementation of the mutation. This new plasmid-like element was named pLP100. Differential excision did not affect the copy number of pLP100 at the population level. This region contains a copper efflux pump encoded by , and increased resistance to copper was observed for the mutant strain that was abrogated in the complemented strain. A strain carrying a mutation of and a deletion of the right side recombination site, , showed that overexpression of pLP100 genes and increased copper resistance in the mutant strain were dependent upon excision of pLP100.

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2013-08-01
2024-04-23
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Analysis of the transcriptome of Legionella pneumophila hfq mutant reveals a new mobile genetic element
Microbiology 159, 1649 (2013); https://doi.org/10.1099/mic.0.067983-0
/content/journal/micro/10.1099/mic.0.067983-0
/content/journal/micro/10.1099/mic.0.067983-0
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