DNA target sequence and FNR-dependent gene expression.
FNR proteins are global transcription regulators that respond to fluctuations in environmental oxygen. They recognise a DNA target consisting of an inverted repeat, TTGATN(1)N(2)N(3)N(4)ATCAA (where N(1-4) represents a non-conserved tetrad, NCT). Analysis of 68 known and predicted FNR sites from the Escherichia coli K12 genome revealed a bias toward A or T at positions N(2) and N(3) of the NCT. The effect of the NCT sequence on FNR-dependent transcription in vivo was assessed using a series of class II and class I model promoters with different NCT sequences. Changing the NCT sequence did not affect basal activity but altered anaerobic induction by as much as an order of magnitude. Thus, the NCT sequence is a fundamental component in setting the dynamic range of the FNR switch.
Scott
Colin
C
Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, UK.
Partridge
Jonathan D
JD
Stephenson
James R
JR
Green
Jeffrey
J
D001483:Base Sequence; D001665:Binding Sites; D030541:Databases, Genetic; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000378:metabolism*; D016680:Genome, Bacterial; D007506:Iron-Sulfur Proteins / Q000378:metabolism*; D008957:Models, Genetic; D011401:Promoter Regions, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D029968:Escherichia coli Proteins; C060704:FNR protein, E coli; D007506:Iron-Sulfur Proteins; D014157:Transcription Factors