Previous Article | Next Article ![]()
J. Bacteriol., 04 1995, 1712-1718, Vol 177, No. 7
TJ Merkel, JL Dahl, RH Ebright and RJ Kadner
Transport and utilization of sugar phosphates in Escherichia coli depend on
the transport protein encoded by the uhpT gene. Transmembrane induction of
uhpT expression by external glucose 6-phosphate is positively regulated by
the promoter-specific activator protein UhpA and the global regulator
catabolite gene activator protein (CAP). Activation by UhpA requires a
promoter element centered at -64 bp, relative to the start of
transcription, and activation by CAP requires a DNA site centered at
position -103.5. This DNA site binds the cyclic AMP-CAP complex in vitro,
and its deletion from the promoter reduces transcription activity to 7 to
9% of the wild-type level. Ten uhpT promoter derivatives with altered
spacing between the DNA site for CAP and the remainder of the promoter were
constructed. Their transcription activities indicated that the action of
CAP at this promoter is dependent on proper helical phasing of promoter
elements, with CAP binding on the same face of the helix as RNA polymerase
does. Five CAP mutants defective in transcription activation at class I and
class II CAP-dependent promoters but not defective in DNA binding or DNA
bending (positive control mutants) were tested for the ability to activate
transcription. These CAPpc mutants exhibited little or no defect in
transcription activation at uhpT, indicating that CAP action at uhpTp
involves a different mechanism than that which is used for its action at
other classes of CAP-dependent promoters.
Copyright © 1995, American Society for Microbiology
Transcription activation at the Escherichia coli uhpT promoter by the catabolite gene activator protein
Department of Microbiology, School of Medicine, University of Virginia, Charlottesville 22908.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |