Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ugp operon of Escherichia coli includes genes involved in the uptake of sn-glycerol-3-phosphate and glycerophosphoryl diesters and belongs to the pho regulon which is induced by phosphate limitation. This operon has two transcriptional initiation sites, as determined by S1 nuclease mapping of the in vivo transcripts. The downstream promoter has multiple copies of the pho box, the consensus sequence shared by the pho promoters; the upstream promoter has a consensus sequence for the promoters regulated by cyclic AMP and its receptor protein, CRP. PhoB protein, which is the transcriptional activator for the pho regulon, protected the regulatory region with the pho boxes in DNase I footprinting experiments and activated transcription from the downstream promoter in vitro. Studies with transcriptional fusions between ugp and a promoterless gene for chloramphenicol acetyltransferase show that the upstream promoter is induced by carbon starvation in a manner that required the cya and crp genes. PhoB protein may act as a repressor for this upstream promoter, which also overlaps the upstream third pho box. The downstream promoter was induced by phosphate starvation and requires the PhoB protein for its activation as do the other pho regulon promoters. These results suggest that the two promoters function alternately in responding to phosphate or carbon starvation, thus providing the cell with a means to adapt to these physiological stresses.
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PMID:Dual regulation of the ugp operon by phosphate and carbon starvation at two interspaced promoters. 198 50

We have shown that the Escherichia coli phosphate-starvation-inducible psiE gene is regulated by both phosphate and the carbon source by using both lacZ and chloramphenicol acetyltransferase gene (cat) fusions. Yet, under all conditions tested, a single transcriptional start site lying 7 bp downstream of a predicted -10 region was revealed by primer extension analysis. DNase I footprinting showed that the PhoB transcriptional-activator protein protects two predicted pho boxes lying upstream of and near the -35 promoter region. Similar analysis showed that the cyclic AMP (cAMP)-cAMP receptor protein (cAMP-CRP) complex binds a region that overlaps with the downstream pho box. These results, together with measurements of the in vivo psiE promoter activity under various conditions, show that expression of the psiE gene is under direct positive and negative control by PhoB and cAMP-CRP, respectively.
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PMID:Dual transcriptional regulation of the Escherichia coli phosphate-starvation-inducible psiE gene of the phosphate regulon by PhoB and the cyclic AMP (cAMP)-cAMP receptor protein complex. 1098 67

The Vitreoscilla hemoglobin gene (vhb) is expressed under oxygen-limited conditions via an FNR-dependent mechanism. Furthermore, cAMP-CRP has been implicated in its regulation. Recently, VHb protein has been reported to protect a heterologous host from nitrosative stress. In this study we analyzed the regulation of the Vitreoscilla hemoglobin promoter (Pvhb) in Escherichia coli under nitrosative and oxidative stress conditions. Our results show unambiguously that expression of neither VHb nor chloramphenicol acetyltransferase under the control of Pvhb is induced under the experimental conditions used. Thus, a clear discrepancy between in vivo function, i.e. protection against nitrosative stress, and regulation of gene expression is obvious. The regulation of Pvhb reported here is in clear contrast to the expression pattern of flavohemoglobins from various microorganisms, which are generally induced by nitrosative stress. However, the length of Pvhb is only 146 bp and therefore, we cannot rule out that additional regulatory sequences may be located in the upstream region of Pvhb.
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PMID:Vitreoscilla hemoglobin promoter is not responsive to nitrosative and oxidative stress in Escherichia coli. 1285 79