A physiological role for DNA supercoiling in the osmotic regulation of gene expression in S. typhimurium and E. coli

Higgins, C. F., Dorman, C. J., Stirling, D. A., Waddell, L., Booth, I. R., May, G. and Bremer, E. (1988) A physiological role for DNA supercoiling in the osmotic regulation of gene expression in S. typhimurium and E. coli. Cell, 52(4), pp. 569-584. (doi: 10.1016/0092-8674(88)90470-9) (PMID:2830029)

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Abstract

The proU locus encodes an osmotically inducible glycine betaine transport system that is important in the adaptation to osmotic stress. We present evidence that DNA supercoiling plays a key role in the osmotic induction of proU transcription. An increase in extracellular osmolarity increases in vivo DNA supercoiling, and the expression of proU is highly sensitive to these changes. Furthermore, topA mutations can mimic an increase in osmolarity, facilitating proU expression even in media of low osmolarity in which it is not normally expressed. Selection for trans-acting mutations that affect proU expression has yielded only mutations that alter DNA supercoiling, either in topA or a new genetic locus, osmZ, which strongly influences in vivo supercoiling. Mutations in osmZ are highly pleiotropic, affecting expression of a variety of chromosomal genes including ompF, ompC, fimA, and the bgl operon, as well as increasing the frequency of site-specific DNA inversions that mediate fimbrial phase variation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:May, Dr Gerhard and Stirling, Dr Douglas
Authors: Higgins, C. F., Dorman, C. J., Stirling, D. A., Waddell, L., Booth, I. R., May, G., and Bremer, E.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
Q Science > QH Natural history > QH426 Genetics
Q Science > QR Microbiology
College/School:College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
Journal Name:Cell
Publisher:Cell Press
ISSN:0092-8674
ISSN (Online):1097-4172

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