Linked Life Data

11361339

Source:http://linkedlifedata.com/resource/pubmed/id/11361339

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-5-21
pubmed:abstractText
The plant-pathogenic bacterium Erwinia carotovora subsp. carotovora (Ecc) causes disease mainly by means of a number of extracellular plant cell wall-degrading enzymes (PCWDEs), also referred to as virulence factors. The production of PCWDEs is coordinately activated by the diffusible signal molecule N-acyl-homoserine lactone (HSL) in a population density-dependent manner ("quorum sensing"). ExpI is the enzyme responsible for the synthesis of HSL. The Rsm system negatively regulates the production of PCWDEs. It includes three components: RsmA is an RNA-binding protein which promotes mRNA decay; rsmB is a unique regulator RNA, and RsmC regulates expression of rsmA positively and of rsmB negatively. We report here that in an expI knockout mutant of Ecc strain SCC3193, the levels of rsmA and rsmB RNA are remarkably enhanced in comparison to the wild-type strain, while the level of the rsmC transcript is not affected. The increase in transcription of rsmA in the expI strain represses production of PCWDEs, which in turn leads to the avirulent phenotype of this mutant. In the expI- mutant, addition of exogenous HSL caused repression of rsmA and rsmB transcription to the wild-type level, whereas the expression of rsmC was not affected. Taken together, these data suggest that HSL affects the expression of rsmA, and that this effect is not mediated by RsmC. This specific effect and the previous demonstration that HSL is required for PCWDE production in Ecc support the hypothesis that regulation by quorum sensing in Ecc, in contrast to most other systems already described, requires HSL to repress rsmA transcription, which in turn leads to the activation of PCWDE production. A model is presented that explains how HSL controls the production of PCWDEs by modulating the expression of rsmA.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1617-4615
pubmed:author
pubmed:issnType
Print
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
287-92
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Quorum sensing controls the synthesis of virulence factors by modulating rsmA gene expression in Erwinia carotovora subsp. carotovora.
pubmed:affiliation
Department of Genetics, Institute of Molecular and Cell Biology, Tartu University, Estonia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't