Listeria monocytogenes σB Regulates Stress Response and Virulence Functions
| Autor: | Sharon C. Mithoe, Mark J. Kazmierczak, Martin Wiedmann, Kathryn J. Boor |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2003 |
| Předmět: |
DNA
Complementary Transcription Genetic Molecular Sequence Data Virulence Sigma Factor Biology Microbiology Bacterial Proteins Sigma factor Gene expression Consensus sequence Humans Promoter Regions Genetic Molecular Biology Gene Oligonucleotide Array Sequence Analysis Genetics Molecular Biology of Pathogens Base Sequence Wild type Promoter Gene Expression Regulation Bacterial Listeria monocytogenes Markov Chains Regulon Heat-Shock Response |
| Popis: | While the stress-responsive alternative sigma factor σBhas been identified in different species ofBacillus,Listeria, andStaphylococcus, theσBregulon has been extensively characterized only inB. subtilis.We combined biocomputing and microarray-based strategies to identify σB-dependent genes in the facultative intracellular pathogenListeria monocytogenes. Hidden Markov model (HMM)-based searches identified 170 candidateσB-dependent promoter sequences in the strain EGD-e genome sequence. These data were used to develop a specialized, 208-gene microarray, which included 166 genes downstream of HMM-predicted σB-dependent promoters as well as selected virulence and stress response genes. RNA for the microarray experiments was isolated from both wild-type and ΔsigBnull mutantL. monocytogenescells grown to stationary phase or exposed to osmotic stress (0.5 M KCl). Microarray analyses identified a total of 55 genes with statistically significantσB-dependent expression under the conditions used in these experiments, with at least 1.5-fold-higher expression in the wild type over thesigBmutant under either stress condition (51 genes showed at least 2.0-fold-higher expression in the wild type). Of the 55 genes exhibiting σB-dependent expression, 54 were preceded by a sequence resembling the σBpromoter consensus sequence. Rapid amplification of cDNA ends-PCR was used to confirm the σB-dependent nature of a subset of eight selected promoter regions. Notably, theσB-dependentL. monocytogenesgenes identified through this HMM/microarray strategy included both stress response genes (e.g.,gadB,ctc, and the glutathione reductase genelmo1433) and virulence genes (e.g.,inlA,inlB, andbsh). Our data demonstrate that, in addition to regulating expression of genes important for survival under environmental stress conditions, σBalso contributes to regulation of virulence gene expression inL. monocytogenes.These findings strongly suggest thatσBcontributes toL. monocytogenesgene expression during infection. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|