Discoordinate gene expression ofgyrA andgyrB in response to DNA gyrase inhibition inEscherichia coli

1997 ◽  
Vol 37 (1) ◽  
pp. 53-69 ◽  
Author(s):  
Susanne Neumann ◽  
Ariel Quiñones
Keyword(s):  
Gene Expression ◽  
Dna Gyrase ◽  
Inescherichia Coli

Protein A gene expression is regulated by DNA supercoiling which is modified by the ArlS–ArlR two-component system of Staphylococcus aureus

Microbiology ◽  
2004 ◽  
Vol 150 (11) ◽  
pp. 3807-3819 ◽  
Author(s):  
Bénédicte Fournier ◽  
André Klier
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Virulence Genes ◽  
Protein A ◽  
Dna Gyrase ◽  
Dna Supercoiling ◽  
Two Component System ◽  
Component System ◽  
High Osmolarity ◽  
Two Component

Bacterial pathogens such as Staphylococcus aureus undergo major physiological changes when they infect their hosts, requiring the coordinated regulation of gene expression in response to the stresses encountered. Several environmental factors modify the expression of S. aureus virulence genes. This report shows that the expression of spa (virulence gene encoding the cell-wall-associated protein A) is down-regulated by high osmolarity (1 M NaCl, 1 M KCl or 1 M sucrose) in the wild-type strain and upregulated by novobiocin (a DNA gyrase inhibitor that relaxes DNA). A gyrB142 allele corresponding to a double mutation in the B subunit of DNA gyrase relaxed DNA and consequently induced spa expression, confirming that spa expression is regulated by DNA topology. Furthermore, in the presence of novobiocin plus 1 M NaCl, a good correlation was observed between DNA supercoiling and spa expression. The ArlS–ArlR two-component system is involved in the expression of virulence genes such as spa. Presence of an arlRS deletion decreased the effect of DNA supercoiling modulators on spa expression, suggesting that active Arl proteins are necessary for the full effect of DNA gyrase inhibitors and high osmolarity on spa expression. Indeed, evidence is provided for a relationship between the arlRS deletion and topological changes in plasmid DNA.

Sign in / Sign up

Export Citation Format

Share Document