Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The syntheses of stable ribosomal ribonucleic acid (RNA) and transfer RNA in bacteria depend on the concentration and activity of RNA polymerase and on the fraction of active RNA polymerase synthesizing stable RNA. These parameters were measured in Escherichia coli B/r after a nutritional shift-up from succinate-minimal to glucose-amino acids medium and were found to change in complex patterns during a 1- to 2-h period after the shift-up before reaching a final steady-state level characteristic for the postshift growth medium. The combined effect of these changes was an immediate, one-step increase in the exponential rate of stable RNA synthesis and thus of ribosome synthesis. This suggests that the distribution of transcribing RNA polymerase over ribosomal and nonribosomal genes and the polymerase activity are continuously adjusted during postshift growth to some growth-limiting reaction whose rate increases exponentially. It is proposed that this reaction is the production of amino-acylated transfer RNA and that is exponentially increasing rate results in part from a gradually increasing concentration of aminoacyl transfer RNA synthetases after a shift-up. This idea was tested and is supported by a computer simulation of a nutritional shift-up.
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PMID:Synthesis and function of ribonucleic acid polymerase and ribosomes in Escherichia coli B/r after a nutritional shift-up. 615 73

For Escherichia coli B/r growing in glucose minimal medium, the following parameters of RNA synthesis remained invariant between 20 and 40 degrees C: RNA polymerase concentration (RNA polymerase/mass), rRNA and tRNA concentration (RNA/mass), RNA polymerase activity (fraction of total RNA polymerase actively engaged in RNA chain elongation), and stable RNA synthesis relative to total RNA synthesis. The following parameters increased 3.4-fold over the same temperature range: rRNA chain elongation rate, guanosine tetraphosphate (ppGpp) concentration, and culture growth rate. Above 40 degrees C, the changes became more complex, and the growth rate began to decrease. The observation that most RNA synthesis parameters are temperature invariant despite the increase of ppGpp suggests that the mechanism of RNA synthesis control by ppGpp, assumed to involve an interaction of RNA polymerase wtih ppGpp, is itself temperature dependent such that, with increasing temperature, higher concentrations of ppGpp are required to affect the RNA polymerase.
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PMID:Temperature dependence of RNA synthesis parameters in Escherichia coli. 617 24

The Saccharomyces cerevisiae gene encoding the glycolytic enzyme pyruvate kinase has been isolated by complementation of a pyk mutant with DNA from a wild type yeast genomic library. Pyruvate kinase enzyme activity is 20-fold higher in the transformant compared to the parental strain and is glucose inducible. The cloned gene has been localized by hybridization of DNA fragments to yeast poly(A+) RNA and by complementation of the mutant defect with select subclones. A DNA sequence of 2885 nucleotides encoding a protein of 499 amino acids is reported. A polypeptide chain of 34 residues of the deduced yeast amino acid sequence closely resembles a peptide sequence at the ADP binding site of bovine muscle pyruvate kinase. The 5' end of the pyruvate kinase mRNA has been mapped and starts within the DNA sequence CAAG at -38 to -27 nucleotides upstream from the first ATG. We note that the sequence PyAAPu in this region appears to be a common consensus site for yeast RNA polymerase II transcriptional starts.
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PMID:The isolation, characterization, and sequence of the pyruvate kinase gene of Saccharomyces cerevisiae. 618 93

The ability of indole derivatives to facilitate RNA polymerase transcription of the L-arabinose operon in Escherichia coli was shown to require the catabolite activator protein (CAP) as well as the araC gene product. Adenosine 3',5'-monophosphate (cAMP) was not obligatory for araBAD transcription when the cells were grown in the presence of 1 mM indole-3-acetic acid or in the presence of indole-3-acetamide, indole-3-propionic acid, indole-3-butyric acid, or 5-hydroxyindole-3-acetic acid. However, these indole derivatives were unable to circumvent the cAMP requirement for the induction of the lactose and the maltose operons. Catabolic repression occurred when glucose was added to cells grown in the presence of L-arabinose and 1 mM indoleacetic acid or 1 mM cAMP. This effect was reversed at higher concentrations of indoleacetic acid or cAMP. The induction and the catabolite repression phenomena were quantitated by measuring the differential rate of synthesis of L-arabinose isomerase (the araA gene product). These results indicated that indole metabolites from various living systems may regulate gene expression and may be involved in "metabolite gene regulation."
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PMID:Metabolite gene regulation of the L-arabinose operon in Escherichia coli with indoleacetic acid and other indole derivatives. 624 2

Oral administration of a 70% solution of sucrose to starved adult rats resulted 1 h after feeding in a 3.5-fold stimulation of intestinal chromatin template activity assayed in vitro using E. coli RNA polymerase. A similar stimulatory effect was observed with fructose, whereas glucose exhibited a weaker effect, indicating that the nature of the ingested carbohydrate may have a direct effect on the extent of intestinal chromatin template activation.
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PMID:Stimulation of intestinal chromatin template activity by dietary carbohydrates in adult rats. 633 63

A number of rifampicin resistance mutations which have been mapped in the region of the rpoB gene, cause an increase in the activity level of a catabolite sensitive uridine phosphorylase (udp) gene. This effect is observed in bacterial cells deficient for the active protein repressor cytR, controlling expression of the udp gene. In cytR mutant cells grown on the medium containing glucose, the level of uridine phosphorylase is further increased by a factor of 1,5 to 2 under the influence of rif-r mutations. Concomitantly, the activity of some other catabolite sensitive genes controlled by the cytR protein is also increased on the medium with glucose. The data obtained suggest that the RNA polymerase beta-subunit participates in regulation of some catabolite sensitive genes.
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PMID:[Mutations of resistance to rifampicin leading to increased activity of the uridine phosphorylase gene in Escherichia coli]. 635 8

The araBAD promoter is defined, in part, by two types of cis-acting constitutive mutations, araIc at position -35 and araXc at position -10. Subcloning experiments demonstrated that the araIc and araIcXc promoters require DNA sequence information out to position -53 to -56 for maximum constitutive expression. This is 8 to 10 base pairs more DNA than is generally thought to be necessary for RNA polymerase interaction. The -53 to -56 region is required for glucose repression, suggesting that an additional factor interacts in this region and is necessary for maximum expression.
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PMID:Functional limits of the araIc promoter suggest an additional regulatory site for araBAD expression. 637 Sep 54

By transformation analysis, a mutation (crsE1), which makes Bacillus subtilis cells able to sporulate in the presence of relatively high concentrations of glucose and other carbon sources, was mapped in the rpoBC operon. The effect of crsE1 mutation can be suppressed by another mutation in the same operon, rfm11, which confers resistance to rifamycin. Mutants carrying stv or std mutations, which are also located in the rpoBC operon, showed partial resistance to catabolites in sporulation. It appears therefore that a change in the structure or synthesis of RNA polymerase may alter the response of cells to the inhibitory effect of catabolites on sporulation.
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PMID:A catabolite-resistance mutation is localized in the rpo operon of Bacillus subtilis. 643 May 35

Yeast mitochondrial RNA polymerase is a nuclear-coded protein of approximately 90,000 daltons comprised of two 45,000-dalton subunits of pI 6.9 to 7.0. To investigate the nature of the initial translation product of the RNA polymerase, we have analyzed those products of a cell-free translation system directed by yeast RNA that are immunoreactive with antibodies to the 45,000-dalton peptide of polymerase. A precursor of one or more of the subunits of the polymerase, 2,000 daltons later than the mature product, has been characterized using immunoreaction, immunocompetition, and peptide digestion. The role of transcription of the polymerase gene in catabolite repression of mitochondrial development has been investigated by analyzing the changes in cell-free synthesis of the RNA polymerase precursor during glucose and raffinose growth. The results indicate an increase in precursor synthesis and probably in the corresponding transcript abundance during glucose derepression. In contrast, the precursor is present at high levels until stationary phase during raffinose growth. These data indicate the involvement of increased transcription of the polymerase gene in the process of derepression.
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PMID:The biogenesis and regulation of yeast mitochondria RNA polymerase. 704 Mar 74

In spite of the generally well-coordinated synthesis of RNA polymerase core enzyme subunits (alpha, beta and beta') in Escherichia coli, a situation was found during the growth transition from exponential to stationary phase in which this coordination was broken (the order of differential repression being alpha leads to beta' leads to beta; Kawakami et al. (1979). The present study indicates that, during a certain period of the growth transition, twice as much beta subunit is synthesized as beta' subunit and the overproduced beta subunit accumulates as the assembly intermediate alpha 2 beta complex, which is rapidly and preferentially degraded. Two independent factors, i.e., carbon source down-shift and oxygen depletion, were examined separately for their influence on the coordinated regulation of the synthesis of RNA polymerase subunits. The depletion of glucose added as a sole carbon source was accompanied by repression of the synthesis of all core enzyme subunits, while under the same conditions the differential rate of sigma subunit synthesis increased. In contrast, the sudden ending of the oxygen supply resulted in specific repression of the synthesis of only beta and beta' subunits but not of sigma and alpha subunits. The latter result may be explained by the autogenous repression of the rpoBC genes by a temporal increase in the amount of unused cytoplasmic RNA polymerase.
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PMID:Biosynthesis of RNA polymerase in Escherichia coli. XII. Noncoordinate synthesis of core enzyme subunits after suppression of cell growth. 704 23


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