Abstract
The Escherichia coli K-12 gene hmp encodes the flavohemoglobin Hmp. A hmp promoter Φ(hmp-lacZ)-operon fusion was constructed in the chromosome and its activity measured during the growth cycle. Logarithmically growing cultures had low levels of Φ(hmp-lacZ) expression, which increased two-fold at the onset of stationary phase in rich medium. The effect was abolished in a strain carrying a null allele of the gene rpoS encoding the stationary phase-specific sigma subunit of RNA polymerase σS. A himA mutation resulted in a 1.5-fold increase in expression of Φ(hmp-lacZ), but did not affect growth phase-dependent regulation. A single transcriptional start site was found for hmp, located 38 bp upstream of the initiation codon. Putative Fnr boxes at positions −2 to +11 occur in the hmp promoter region.
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Received: 9 September 1996 / Accepted: 8 January 1997
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Membrillo-Hernández, J., Cook, G. & Poole, R. Roles of RpoS (σS), IHF and ppGpp in the expression of the hmp gene encoding the flavohemoglobin (Hmp) of Escherichia coli K-12. Mol Gen Genet 254, 599–603 (1997). https://doi.org/10.1007/s004380050457
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DOI: https://doi.org/10.1007/s004380050457