Affiliation:
1. Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
Abstract
ABSTRACT
In
Escherichia coli
, one of the best understood microorganisms, much can still be learned about the basic interactions between transcription factors and promoters. When a cAMP-deficient
cya
mutant is supplied with maltose as the main carbon source, mutations develop upstream from the two genes
malT
and
sdaC
. Here, we explore the regulation of the two promoters, using fluorescence-based genetic reporters in combination with both spontaneously evolved and systematically engineered
cis
-acting mutations. We show that in the
cya
mutant, regulation of
malT
and
sdaC
evolves toward cAMP-independence and increased expression in the stationary phase. Furthermore, we show that the location of the cAMP receptor protein (Crp) binding site upstream of
malT
is important for alternative sigma factor usage. This provides new insights into the architecture of bacterial promoters and the global interplay between Crp and sigma factors in different growth phases.
IMPORTANCE
This work provides new general insights into (1) the architecture of bacterial promoters, (2) the importance of the location of Class I Crp-dependent promoters, and (3) the global interplay between Crp and sigma factors in different growth phases.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology