Affordable Access

Titration of DnaA protein by oriC DnaA-boxes increases dnaA gene expression in Escherichia coli.

Authors
  • F G Hansen
  • S Koefoed
  • L Sørensen
  • T Atlung
Publication Date
Jan 01, 1987
Source
PMC
Keywords
Disciplines
  • Biology
License
Unknown

Abstract

Binding of the DnaA protein to its binding sites, the DnaA-boxes (TTATCCACA), was measured by a simple physiological approach. The presence of extra DnaA-boxes in growing cells leads to a derepression of dnaA gene expression, measured as beta-galactosidase activity of a dnaA-lacZ fusion polypeptide. Different DnaA-boxes caused different degrees of derepression indicating that the DnaA protein requires sequences in addition to the DnaA-box for efficient binding. The DnaA-boxes in oriC might act cooperatively in binding of the DnaA protein. The derepressed levels of DnaA protein obtained in a strain carrying an oriC+-pBR322 chimera were very high and sufficient to activate oriC on the chimeric plasmid, which was maintained at a copy number more than three times that of pBR322.

Report this publication

Statistics

Seen <100 times