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)

Analysis of the synthetic rate of individual protein species at various times after complete inhibition of transcription with either streptolygidin or rifampicin was carried out by two-dimensional polyacrylamide electrophoresis of total Escherichia coli cell extracts. The decay rate of the potential to synthesize different proteins was assumed to be equal to the functional decay rate of the corresponding mRNA. We conclude the following: (a) The tufA and tufB messengers have different half lives (3.0 and 2.4 min, respectively). (b) Different genes within the same transcriptional unit can have different half lies (S7, EGF and EFTuA--2.5, 3.8 and 3.0 min, respectively). (c) There is at least a twenty-fold variation in individual mRNA half lives in E. coli; ribosomal protein S1 mRNA was observed to have the shortest half life in the cell (40 sec), while the longest observed half life was approximately 20 min (all values at 30 degrees C). (d) Addition of rifampicin increases the absolute rate of RNA polymerase subunit alpha and beta synthesis two-fold. (e) The induction of the synthesis of alpha subunit of RNA polymerase takes place without a concomitant induction of ribosomal protein S4 and L17, which are reported to be on either side of alpha in the same transcriptional unit.
Mol Gen Genet 1978 Nov 09
PMID:Functional mRNA half lives in E. coli. 36 81

Escherichia coli strains with mutations rho-115, rho-ts15, rho-101 (psu-1) or rho-102 (psu-2) are more sensitive ("supersensitive") to rifampicin than isogenic parent strains, as measured by growth rate in broth and colony forming efficiency on solid media with 5, 10, or 20 microgram of rifampicin per ml. There is no change in sensitivity of rho mutants to the antibiotics penicillin, erythromycin, chloramphenicol, or the detergent desoxycholate. The rho-101 or rho-102 mutations confer rifampicin supersensitivity at 32 degrees C but not 42 degrees C. Mutants of a rho-115 strain that have lost polarity suppression can be isolated by selection for rifampicin resistance. This phenotype, Sur, is not due to reversion of the original rho gene mutation but to a second mutation perhaps in the gene for rho protein or the gene for the beta subunit of RNA polymerase. One class of Sur mutation, occurring in rho-115 cells isolated as resistant to 20 microgram of rifampicin per ml, is co-transducible with the marker ilv, and the gene order is rbs-ilv-sur-38. A model suggested by this map position is that the mutations rho-115 and sur-38 define the domain of rho protein which interacts with the beta subunit of RNA polymerase.
Mol Gen Genet 1979 Jan 16
PMID:Rifampicin supersensitivity of rho strains of E. coli, and suppression by sur mutation. 37 96

The adjacent genes rpoB and rpoC code for the beta and beta' subunits of RNA polymerase in Escherichia coli, and are cotranscribed in the order given. The nearest known genes to rpoB are rplL and rplA,J,K, which code for ribosomal proteins, and which are transcribed in the same direction as the polymerase genes. It has been suggested that rpoBC may be distal elements of a larger operon including these ribosomal genes. To test this possibility we have cloned a segment of DNA, derived by endoR. HindIII digestion from the rpoBC-transducing bacteriophage lambdarifd18, in the replacement vector NMlambda761. The structure of the lambdarpoBC bacteriophages so produced is such that the inserted DNA can be transcribed from lambda promoters, allowing us to confirm that it carries intact rplL, rpoB, and rpoC genes. We have studied these bacteriophages as lysogens in rec+ and rec bacteria, and by infection of UV-irradiated bacterial strains in which lambda promoters are either repressed or active. The results indicate that the cloned DNA contains at most a very weak promoter for the above genes, in contrast to that present in the larger segment of bacterial DNA carried by lambdarifd18. We have in the same way cloned the adjacent bacterial HindIII-fragment of lambdarifd18 DNA, and have found that it displays vigorous autonomous expression of the tufB, rplA, and rplK genes. We conclude that rpoB and C are obligatorily co-transcribed with rplL, from a promoter located outside the DNA segment cloned in lambdarpoBC. We discuss the evidence for the existence of a regulatory site, rpoU, located between rplL and rpoB.
Mol Gen Genet 1979 Jan 31
PMID:Evidence for co-transcription of the RNA polymerase genes rpoBC with a ribosomal protein gene of escherichia coli. 37 8

We studied the rate of synthesis of beta-and beta'-subunits of DNA-dependent RNA polymerase and the rate of beta-polypeptide mRNA synthesis in rifampicin-treated bacteria. The chosen antibiotic doses did not significantly inhibit the total RNA and protein synthesis in rifampicin-sensitive bacteria. For RNA-DNA hybridization experiments a pOD162 plasmid was constructed carrying a fragment of the rpoB gene and no other chromosome DNA regions. It was found that low doses of rifampicin cause an absolute and a relative increase in the rate of synthesis of the specific mRNA for the beta-subunit, suggesting a stimulation of the corresponding gene transcription and excluding the possibility of a less pronounced inhibition of the rpoB gene expression compared to that of most other genes. However the relative acceleration of transcription is substantially higher than the absolute one. The stimulating effect of rifampicin on the beta-polypeptide synthesis is also demonstrated in a coupled system of transcription and translation directed by lambda rifd47 DNA. The possible mechanisms of the rifampicin action are discussed.
Mol Gen Genet 1979 May 23
PMID:The effect of rifampicin upon the transcription of RNA polymerase beta-gene in Escherichia coli. 38 37

Fragments of lambda drifd 18 DNA with different end-points within the set of structural genes of ribosomal proteins L11 (RPLK), Li (rplA), L10 (rplJ) and L12 (rplL) as well as the beta (rpoB) ANd beta' (rpoC) subunits of RNA polymerase have been cloned on plasmids. These plasmids were transformed in host cells which were mutant for each of the genes, enabling expression of both wild-type (plasmid-borne) and mutant (chromosomal) genes to be differentiated. On the basis of these results we propose the following genetic structure for the region: rplK and rplA are in one operon; rplL, rpoB and rpoC are in a second. Our data suggest the possibility that rplJ is by itself in an operon situated between the other two.
Mol Gen Genet 1979 May 23
PMID:Expression of Escherichia coli ribosomal protein and RNA polymerase genes cloned on plasmids. 38 41

Polyriboinosinic acid (poly I) inhibits initiation of transcription by binary complexes formed between Adenovirus 2 DNA and E. coli RNA polymerase holoenzyme. In the presence of poly I, just as in the presence of rifampicin, initiation of transcription exhibits a sigmoidal dependence on the temperature at which the binary complexes are formed. This indicates that I (closed) complexes between Ad 2 DNA and RNA polymerase are rapidly inactivated by poly I, but that RS (open) complexes are relatively resistant. However, even among the RS complexes, at least two classes can be distinguished on the basis of the degree to which they are resistant to poly I: RS-1 complexes are somewhat sensitive to poly I (half-time of inactivation approximately 10 min) while RS-2 complexes are almost completely resistant to the inhibitor (half-time of inactivation approximately 10 h). For both types of RS complex, the degree of sensitivity to poly I is ionic strength-dependent.
Mol Gen Genet 1979 May 23
PMID:Inactivation of E. coli RNA polymerase by polyriboinosinic acid: heterogeneity of RS complexes. 38 42

Minicells segregated from Escherichia coli chi925 carrying a drug-resistance plasmid were separated from nucleated cells by differential centrifugation and purified by rate-zonal centrifugation in sucrose gradients. Minicells purified in this way were capable of donating the plasmid to nucleated cells. They also incorporated thymidine, uridine and methionine into macromolecules. Methods are described for purification of plasmid-containing minicells on a scale large enough to allow isolation of DNA, DNA polymerase and RNA polymerase in sufficient quantities for studies of enzymes involved in replication and transcription of plasmid DNA.
J Gen Microbiol 1979 Apr
PMID:Isolation by differential and zonal centrifugation of minicells segregated by Escherichia coli. 38 90

2,6-diaminpurine (DAP) selectively inhibited mitochondrial protein synthesis in yeast cells with concomitant failure of cells to grow in non-fermentable (yeast extract, glycerol) medium. The selectivity was pronounced in all strains tested (15) nearly all of which were able to grow in yeast extract, glucose medium containing 5 mg/ml DAP (maximum solubility) whereas growth was arrested in all strains at 250-500 microgram/ml DAP in the glycerol medium. The inhibition was reversed by further addition of adenine to the culture medium. RNA synthesis in rat liver mitochondria was depressed by DAP suggesting that the analogue affected RNA polymerase activity. There was no evidence of nuclear mutagenicity by DAP but resistance to the antibiotics chloramphenicol and oligomycin was induced by the drug. Genetic evidence, although limited, indicated that the resistance mutations were cytoplasmic. The mitochondrial petite mutation was also induced by DAP but only at comparatively high concentrations. The mutagenic effects were seen only in the glycerol medium.
Mol Gen Genet 1979 Jun 20
PMID:Mitochondrial activity of 2,6-diaminopurine in Saccharomyces cerevisiae. 38 52

Two hundred strains of Saccharomyces cerevisiae temperature sensitive for RNA synthesis were selected and screened in crude extracts for DNA-dependent RNA polymerase activities. One strain was isolated which had only residual in vitro RNA polymerase B activity. In normal growth conditions total RNA, poly A+ RNA and protein synthesis were indistinguishable from those of the wild type strain at 23 degrees C and after shift to 37 degrees C. A temperature sensitive phenotype was detected only when rpoB containing strains were grown in adverse conditions. The mutant character showed mendelian segregation and was coexpressed with the wild type character in heterozygous diploids. Residual enzyme activity was characterised in crude extracts using synthetic polymers and natural templates in different ionic conditions.
Mol Gen Genet 1979 Jun 07
PMID:Isolation and characterisation of a strain of Saccharomyces cerevisiae deficient in in vitro RNA polymerase B(II) activity. 38 33

Through cloning and deletion experiments on ColEl hybrids the rpoB gene (Rifr) was located on a physical restriction map; RNA polymerase binding studies showed no binding site within the structural gene. The genetic data and RNA polymerase binding studies lead to the conclusion that rp/L and rpoB are dependent upon a common promoter.
Mol Gen Genet 1979 Jun 07
PMID:Deletions, insertions and rearrangements affecting rpoB gene expression. 38 38


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