Transcription regulation of the colicin K cka gene reveals induction of colicin synthesis by differential responses to environmental signals.

ABSTRACT: Colicin-producing strains occur frequently in natural populations of Escherichia coli, and colicinogenicity seems to provide a competitive advantage in the natural habitat. A cka-lacZ fusion was used to study the regulation of expression of the colicin K structural gene. Expression is growth phase dependent, with high activity in the late stationary phase. Nutrient depletion induces the expression of cka due to an increase in ppGpp. Temperature is a strong signal for cka expression, since only basal-level activity was detected at 22 degrees C. Mitomycin C induction demonstrates that cka expression is regulated to a lesser extent by the SOS response independently of ppGpp. Increased osmolarity induces a partial increase, while the global regulator integration host factor inhibits expression

SUBMITTER: Kuhar I 

PROVIDER: S-EPMC103702 | biostudies-literature | 1999 Dec

REPOSITORIES: biostudies-literature