Global regulatory mechanisms affect virulence gene expression in Bordetella pertussis
| Autor: | Heike Deppisch, Heinke Graeff-Wohlleben, Roy Gross |
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| Rok vydání: | 1995 |
| Předmět: |
Aminocoumarins
DNA Bacterial Bordetella pertussis Transcription Genetic Molecular Sequence Data Virulence Biology DNA gyrase Regulon Bacterial Proteins Coumarins Genes Regulator Genetics Topoisomerase II Inhibitors RNA Messenger Promoter Regions Genetic Molecular Biology Gene Base Sequence DNA Superhelical Promoter Gene Expression Regulation Bacterial biology.organism_classification DNA supercoil Nucleic Acid Conformation Pertactin Novobiocin Transcription Factors |
| Zdroj: | Moleculargeneral genetics : MGG. 247(1) |
| ISSN: | 0026-8925 |
| Popis: | The influence was investigated of DNA gyrase-inhibiting drugs on the expression of various genes of Bordetella pertussis. We show that the promoters of the virulence regulatory bvg locus and of several bvg-regulated virulence factors, such as the fha, ptx, cya, fim2 and vrg6 loci are very sensitive to the action of novobiocin and coumermycin A, as reflected by transcriptional differences in gene expression. Inhibition of DNA gyrase by the drugs led to a strong decrease in transcription of these genes. Interestingly, one gene belonging to the bvg virulence regulon behaved differently: the promoter of the prn locus, coding for the outer membrane protein pertactin, involved in bacterial adhesion to eukaryotic cells, was induced after inhibition of DNA gyrase. The expression of other genes not belonging to the bvg regulon, such as those encoding porin (POR) and superoxide dismutase (SodB), were not, or only weakly, affected by the drugs. This demonstrates that with respect to drug-induced changes in DNA supercoiling there exist different types of promoters in B. pertussis. In an attempt to identify additional regulatory mechanisms that may modulate virulence gene expression, we investigated the effect of various environmental stimuli on the stability of the bvg-regulated vrg6 and the bvg-independent sodB transcripts. We found that some signals transduced via by the BvgS sensor protein, such as variations in the growth temperature or the presence of nicotinic acid, exerted a strong effect on the half life of these transcripts, whereas another modulating agent, MgSO4, did not have any influence. These data suggest that the regulation of individual factors of the Bvg virulence regulon may be influenced by additional mechanisms, possibly involving differential effects on gene expression induced by changes in the DNA topology and the half-life of the respective mRNA. |
| Databáze: | OpenAIRE |
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