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An overlap between osmotic and anaerobic stress responses: a potential role for DNA supercoiling in the coordinate regulation of gene expression
Author(s) -
Bhriain N. Ni,
Dorman C. J.,
Higgins C. F.
Publication year - 1989
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1989.tb00243.x
Subject(s) - biology , dna supercoil , osmotic shock , gene , dna , anaerobic exercise , gene expression , regulation of gene expression , expression (computer science) , genetics , microbiology and biotechnology , computational biology , physiology , dna replication , computer science , programming language
Summary The regulation of several genes in response to osmotic and anaerobic stress has been examined. We have demonstrated a clear overlap between these two regulatory signals. Thus, the osmotically induced proU and ompC genes require anaerobic growth for optimum induction while the anaerobically induced tppB gene is also regulated by osmolarity. Furthermore, normal expression of tppB and ompC requires the positive regulatory protein OmpR, yet this requirement can be partially, or even fully, overcome by altering the growth conditions. Finally, the pleiotropic, anaerobic regulatory locus, oxrC , is also shown to affect expression of the osmoticalty regulated proU gene. The oxrC mutation is shown to affect the level of negative supercoiling of plasmid DNA and its effects on gene expression can be explained as secondary consequences of altered DNA topology. We suggest that there is a class of ‘stress‐regulated’ genes that are regulated by a common mechanism in response to different environmental signals. Furthermore, our data are consistent with the notion that this regulatory overlap is mediated by changes in DNA supercoiling in response to these environmental stresses.