RNA polymerase, PurR and MetR interactions at the glyA promoter of Escherichia coli

Abstract

In Escherichia coli, the MetR and PurR proteins positively and negatively regulate g/yA gene expression, respectively. A DNase I footprint analysis showed that both proteins bind independently to the g/yA control region. The PurR protein blocks RNA polymerase (RNAP) from binding to the g/yA promoter. The presence of hypoxanthine, the co-repressor of PurR, increases the ability of PurR to prevent RNAP binding, providing a model for repression of the g/yA gene by PurR. In contrast, MetR alters the RNAP footprint pattern of the g/yA control region. In addition, the MetR footprint is increased in the presence of RNAP, suggesting that the two proteins might interact.

PipMaker—A Web Server for Aligning Two Genomic DNA Sequences

“…From the alignment shown in Figure 5C, one can see that the promoters for each gene are conserved and long identical segments are seen between the promoters. These conserved regions correspond to previously characterized binding sites for PurR and MetR (Lorenz and Stauffer 1996), the latter of which is involved in the induction of hmpA by nitric oxide (Membrillo-Hernandez et al 1998). This gene encodes a flavohemoglobin with a nitric oxide dioxygenase activity (Gardner et al 1998;Hausladen et al 1998).…”

A novel mechanism for upregulation of the Escherichia coli K‐12 hmp (flavohaemoglobin) gene by the ‘NO releaser’, S‐nitrosoglutathione: nitrosation of homocysteine and modulation of MetR binding to the glyA‐hmp intergenic region

“…We observed that conditions reported to induce or repress the expression of glyA also modify hmp expression in the opposite manner. For example, addition of purines to the growth medium results in repression of the glyA gene by the global regulator PurR (Steirt et al ., 1990; Lorenz and Stauffer, 1995; 1996c). However, when cells carrying Φ( hmp–lacZ ) 1 (strain RKP2178) (containing all the glyA ‐ hmp intergenic promoter region) were treated with the purine, inosine (0.37 mM), a 2.3‐fold induction of hmp expression was observed (data not shown).…”

“…coli glyA‐hmp intergenic promoter region. The location of the +1 transcription initiation site and the −10 and −35 regions are indicated, as well as the ribosome binding site (RBS) (Lorenz and Stauffer, 1996c; Membrillo‐Hernández et al ., 1997b). MetR and PurR binding sites (Lorenz and Stauffer, 1996c) are shown by boxes and the horizontal lines indicate protected regions for RNA polymerase (Plamann and Stauffer, 1983).…”

Cloning and complete nucleotide sequence of Acinetobacter radioresistens CMC-1 AglyA gene encoding serine hydroxymethyltransferase

“…The fact that the addition of 0.1% olive oil, ¢sh oil, or tributyrin to the medium results in stimulating A. radioresistens cells growth and a four-fold increase in AglyA mRNA, which is consistent with SHMT activity increase, indicated that some component(s), derived from the metabolism of lipid inducers, may regulate the expression of the AglyA gene at the transcriptional level. Furthermore, analysis of the 5P-non-coding regions of the AglyA gene suggested that expression of SHMT might be regulated by the MetR-like protein, as reported for the E. coli glyA gene [12]. Further studies involving gel-retardation assays or DNase I footprint analysis may help to elucidate whether the putative sequence for MetR-like binding is essential for regulating the AglyA gene expression.…”

“…A possible ribosome- binding site (RBS), AGGA, was present 7 bp upstream from the presumptive start codon, ATG. A DNA sequence analysis revealed that two regions, which are centered at bp 3123 and 395 relative to the +1 translation start site of Acinetobacter radioresistens AglyA, display a striking degree of homology to the E. coli glyA consensus-binding motif for MetR, a DNA-binding protein of the LysR-family that also positively regulates glyA gene expression [12]. The sequence of two regions, (5P-TGAAACAT-GAGCT) and (5P-TGAGCAAAGTTCA) which have six out of nine and eight out of nine nucleotides that match to the consensus MetR-binding sequence of E. coli (5P-TGAANNT/ANNTTCA), respectively.…”