Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.8 (polynucleotide phosphorylase)
 723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The RNA degradosome is a multienzyme complex that plays a key role in the processing of stable RNAs, the degradation of mRNAs, and the action of small regulatory RNAs. Initially discovered in Escherichia coli, similar or related complexes are found in other bacteria. The core of the RNA degradosome is the essential endoribonuclease, RNase E. The C-terminus of this enzyme serves as a scaffold to which other components of the RNA degradosome bind. These ligands include the phosphorolytic 3'-exonuclease, polynucleotide phosphorylase, the DEAD-box RNA helicase, RhlB, and the glycolytic enzyme, enolase. In addition, the DEAD-box RNA helicases CsdA and RhlE and the RNA binding protein, Hfq, may bind to RNase E in place of one or more of the prototypical components. This chapter describes purification of RNase E (the Rne protein), reconstitution of a minimal degradosome that recapitulates the activity of authentic degradosomes, and methods for the assay of the reconstituted complex.
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PMID:Preparation of the Escherichia coli RNase E protein and reconstitution of the RNA degradosome. 1916 45

OxyS is one of at least three small non-coding RNAs, which affect rpoS expression. It is induced under oxidative stress and reduces the levels of the stationary phase sigma factor RpoS. We analyzed the turn-over of OxyS and rpoS mRNA in early exponential and in stationary growth phase in different E. coli strains to learn more about the mechanisms of processing and about a possible impact of processing on growth-dependent regulation. We could not attribute a major role of RNase E, RNase III, PNPase or RNase II on OxyS turn-over in exponential growth phase. Only the simultaneous lack of RNase E, PNPase and RNase II activity resulted in some stabilization of OxyS in exponential growth phase, implying the action of multiple ribonucleases on OxyS turn-over. A major role of RNase E on OxyS stability was observed in stationary phase and was dependent on the presence of the RNA binding protein Hfq and of DsrA, one of the other small RNAs binding to rpoS mRNA. Our data also confirm a role of RNase III in rpoS turn-over, however, only in exponential growth phase.We conclude that OxyS and rpoS mRNA processing is influenced by different RNases and additional factors like Hfq and DsrA and that the impact of these factors is strongly dependent on growth phase.
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PMID:The influence of Hfq and ribonucleases on the stability of the small non-coding RNA OxyS and its target rpoS in E. coli is growth phase dependent. 2001 54