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Infect Immun. 2014 Jun;82(6):2542-52. doi: 10.1128/IAI.01803-14. Epub 2014 Mar 31.

A putative regulatory genetic locus modulates virulence in the pathogen Leptospira interrogans.

Author information

1
Institut Pasteur, Biology of Spirochetes Unit, Paris, France.

Abstract

Limited research has been conducted on the role of transcriptional regulators in relation to virulence in Leptospira interrogans, the etiological agent of leptospirosis. Here, we identify an L. interrogans locus that encodes a sensor protein, an anti-sigma factor antagonist, and two genes encoding proteins of unknown function. Transposon insertion into the gene encoding the sensor protein led to dampened transcription of the other 3 genes in this locus. This lb139 insertion mutant (the lb139(-) mutant) displayed attenuated virulence in the hamster model of infection and reduced motility in vitro. Whole-transcriptome analyses using RNA sequencing revealed the downregulation of 115 genes and the upregulation of 28 genes, with an overrepresentation of gene products functioning in motility and signal transduction and numerous gene products with unknown functions, predicted to be localized to the extracellular space. Another significant finding encompassed suppressed expression of the majority of the genes previously demonstrated to be upregulated at physiological osmolarity, including the sphingomyelinase C precursor Sph2 and LigB. We provide insight into a possible requirement for transcriptional regulation as it relates to leptospiral virulence and suggest various biological processes that are affected due to the loss of native expression of this genetic locus.

PMID:
24686063
PMCID:
PMC4019197
DOI:
10.1128/IAI.01803-14
[Indexed for MEDLINE]
Free PMC Article

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