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 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.
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PMID:Evidence for co-transcription of the RNA polymerase genes rpoBC with a ribosomal protein gene of escherichia coli. 37 8

The in vitro transcription of chick liver chromatin before and after estrogen treatment was studied. Transcription was by endogenous as well as homologous exogenous RNA polymerase II and the products were analyzed for size and specific vitellogenin sequences. Quantitatively more RNA was synthesized from chromatin of 24 h estrogen-treated (E 24) chicks than from that of untreated chicks. In either case the size of transcribed RNA ranged from 5S to larger than 28S and most was between 5S and 18S. When a fraction enriched in estrogen receptor (E-Rec) complex was added to chromatin from untreated chicks, a dramatic shift of the RNA transcribed into heavier regions occurred. Analysis of RNA transcripts by hybridization to cDNAvit showed an equal number of sequences transcribed from E 24 chromatin and control; however, 13 times more specific sequences were transcribed in the presence of E-Rec complex. The results indicate the E-Rec complex exerts a regulatory function in the specific transcription of the vitellogenin gene.
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PMID:In vitro transcription of vitellogenin sequences on chick liver chromatin. 72 4

The Escherichia coli DNA-dependent RNA polymerase (RPase) holoenzyme (alpha 2 beta beta' sigma) possesses 2 mol equiv of Zn: beta and beta' subunits each contain one Zn ion. An in vitro metal-substitution method developed earlier (method I) was used to remove the two intrinsic Zn ions and then to reconstitute other metal ions into the beta subunit of RPase. One Cd or Hg ion was successfully reconstituted into half-active enzymes (rec-Cd1- or rec-Hg1-RPase), while Mn or Ni ion was not incorporated. A new, simplified in vitro metal-substitution method (method II), which omitted the low-pH treatment and subsequent urea dialysis in method I, was devised in this study. Consequently, Zn or Cd could be incorporated into both the beta and beta' subunits, resulting in rec-Zn2- or rec-Cd2-RPase, respectively. However, only one Hg was incorporated, probably due to steric hindrance by the large size of the Hg ion, while Mn, Ni, or Cr was not bound by the reconstituted enzyme, which instead incorporated only one Zn. Analysis of the metal content of various reconstituted RPases indicated that without low-pH treatment Zn bound to both the beta and beta' subunits when Zn concentrations were higher than 2 X 10(-6)M, but it bound only to the beta' subunit at lower concentrations. Moreover, low-pH treatment destroys the metal binding site in the beta' subunit. The metal sites on the beta and beta' subunits did not have significant affinity for the transition metals such as Mn, Ni, and Cr.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Preparation and characterization of various Escherichia coli RNA polymerases containing one or two intrinsic metal ions. 390 99

We studied the formation of linked circular DNA molecules promoted by the combined action of rec 1 protein and type I topoisomerase of Ustilago maydis. When ATP was added as cofactor to reactions containing rec 1 protein, pairs of homologous circular DNA molecules became linked after addition of topoisomerase. Closed circular duplex molecules could be joined at homologous sites with circular single-stranded molecules or with other circular duplex molecules, provided that homologous single-stranded DNA fragments or RNA polymerase and nucleoside triphosphates were also added. Complexes formed were topologically linked through regions of heteroduplex DNA. When the analog adenylyl-imidodiphosphate was substituted for ATP, nonhomologous pairs of circular DNA molecules became linked.
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PMID:Topological linkage of circular DNA molecules promoted by Ustilago rec 1 protein and topoisomerase. 631 15

The DNA-dependent RNA polymerase (RPase) from Escherichia coli contained 2 mol of Zn/mol of holoenzyme (alpha 2 beta beta' sigma). An in vitro protocol involving sequential denaturation of RPase in 8 M urea and low pH (2.2), in the presence of 10 mM ethylenediaminetetraacetic acid (EDTA), was developed to completely remove the two intrinsic Zn ions. Subsequent reconstitution of the denatured, Zn-free RPase in the absence and presence of 10(-5) approximately 10(-4) M ZnCl2 yielded respectively the inactive apoenzyme and active (50 +/- 10%) RPase containing one Zn ion (rec-Zn1-RPase). Active rec-Cd1-RPase was similarly obtained when CdCl2 instead of ZnCl2 was used in the reconstitution. The use of 65Zn as a tracer in the two-step reconstitution procedure showed that the metal was incorporated into renatured enzyme only in the last step of reconstitution. The subunit location of the incorporated metal was identified to be in the beta subunit by the use of Affi-Gel Blue column chromatography of rec-Cd1-RPase. The analysis of apo- and rec-Zn1-RPases by sucrose density gradient sedimentation showed that the inactive apo-RPase appeared to be consisted of randomly folded protein species with S20,w values ranging from 5 to 18 S, while rec-Zn1-RPase contained a major, active 13S RPase species and a minor, inactive 7.9S species that could be separated by DNA-cellulose column chromatography. Both 13S and 7.9S RPase contained 1 mol of Zn and the five subunits.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intrinsic zinc ion is essential for proper conformation of active Escherichia coli RNA polymerase. 639 24

Preliminary evidence has indicated that the number of nuclear bodies in uterine luminal epithelial cells of the immature rat may be related to the duration of nuclear retention of the estrogen receptor complex (Clark et al., 1978). To test this hypothesis, an ultrastructural analysis of nuclear and cytoplasmic differentiation was performed at 4, 12, 24, 48, and 72 hr after a single injection of estradiol or nafoxidine (synthetic estrogen agonist/antagonist) into 21 day female rats. Variations in nuclear and cytoplasmic differentiation and in the frequency of occurrence of nuclear bodies (simple and complex) were determined and compared with established biochemical changes in the concentration of nuclear estrogen receptor and RNA polymerase activity (Clark et al., 1978). Following nafoxidine there is sustained elevation of the nuclear concentration of the estrogen receptor as well as RNA polymerase I and II activities over the entire 72-hr period. From 4 to 72 hr the height of the luminal epithelial cell as well as the frequency of nuclear bodies increase at linear rates. Through steady expansion of the cytoplasmic membrane system (RER) and Golgi) the relatively undifferentiated epithelial cells of the control uterus are converted progressively into ones equipped for protein secretion. At 72 hr the effects of an estradiol implant resemble closely those observed after a single injection of nafoxidine; these include sustained nuclear receptor occupancy, elevated RNA polymerase activity, epithelial hypertrophy, and high frequency of nuclear bodies. However, after a single injection of estradiol, the luminal epithelial cells become slightly but significantly taller than the control cells and remain close to this size from 24 to 72 hr.; the frequency of nuclear bodies decreases linearly from 4 to 72 hr to fall below the control level. In addition, limited cytoplasmic autolysis is evident from 24 to 72 hr. A single injection of estradiol results in short-term nuclear receptor occupancy and elevated RNA polymerase activities which return to control levels by 24 hr. This collective evidence offers further support to the hypothesis that the duration of nuclear occupancy by the estrogen receptor is reflected in the size of the nuclear body populations in these epithelial target cells. Also during hyperestrogenization, epithelial hypertrophy is accompanied by steady formation of nuclear bodies.
Anat Rec 1981 Dec
PMID:Nuclear bodies as structural indicators of estrogenic stimulation in uterine luminal epithelial cells. 734 May 72

Inactivation of Bacillus subtilis orf1177 in an otherwise Rec+ strain reduced genetic exchange and DNA repair. When the mutation was transferred into a set of recombination-deficient and repair-deficient strains, the DNA repair and recombination ability of the double or triple mutant strains was drastically reduced. B. subtilis Orf1177 protein shares substantial homology with the Escherichia coli Mdf, RecG and UvrB proteins. In vivo analysis of UV-induced mutations suggests that Orf1177 is necessary for strand-specific DNA repair, as is the case for the E. coli MFD protein. Therefore, orf1177 and Orf1177 were termed mfd gene and Mfd protein, respectively. The purified Mfd protein has a native molecular mass of 140 kDa (expected molecular mass 133 kDa). The Mfd protein is a sequence-independent DNA binding protein with weak ATPase activity. The Mfd protein was able to displace in vitro B. subtilis or E. coli RNA polymerase stalled at a lesion. Therefore, Mfd protein appears to target the transcribed strand for repair by recognizing a stalled RNA polymerase and dissociating it from the DNA. In addition, the strong recombination-deficient phenotype of mfd- rec- strains suggest that Mfd protein is involved in homologous DNA recombination.
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PMID:The Mfd protein of Bacillus subtilis 168 is involved in both transcription-coupled DNA repair and DNA recombination. 859 98

A multiplex reverse-transcriptase-PCR (RT-PCR) procedure was developed for the simultaneous detection of porcine epidemic diarrhoea virus (PEDV) and transmissible gastroenteritis virus (TGEV) in preweaning pigs with diarrhoea. The membrane gene of PEDV and the nucleocapsid gene of TGEV were chosen as targets. The PCR products of PEDV and TGEV had molecular sizes of 412 and 612 base pairs, respectively. Primers from PEDV did not react with any TGEV tested and vice versa. In addition, the primers did not react with other pig viruses. The multiplex RT-PCR was able to detect 10 tissue culture-infective doses 50 per cent (TCID50)/ml of PEDV or TGEV with each of the primer sets for PEDV and TGEV, respectively. The RNAS of PEDV and TGEV were detected directly in intestinal and faecal samples from pigs infected experimentally with either virus. The results of the assay correlated well with the results of virus isolation. None of the five control specimens was positive. PEDV was detected in 10 intestinal and nine faecal samples, and among the nine positive faecal samples two were culture-negative. TGEV was also detected in 10 intestinal and nine faecal samples, and among the nine positive faecal samples, three were culture-negative.
Vet Rec 2000 May 27
PMID:Detection and differentiation of porcine epidemic diarrhoea virus and transmissible gastroenteritis virus in clinical samples by multiplex RT-PCR. 1087 84

The pattern of shedding of feline coronavirus (FCoV) was established in 155 naturally infected pet cats from 29 households over periods of up to five years. Viral RNA was detected in faeces by reverse-transcriptase PCR (RT-PCR), and plasma antiviral antibodies by immunofluorescence. The cats rarely shed FCoV in their saliva. Three patterns of FCoV shedding were observed. Eighteen of the cats shed virus continuously, so were persistent, and possibly lifelong, carriers; none of them developed feline infectious peritonitis. Fifty-six cats ceased shedding virus, although they were susceptible to reinfection, and 44 shed intermittently or were being continuously reinfected. Four of the cats were resistant to infection. Seventy-three per cent of the virus shedding episodes lasted up to three months and 95 per cent up to nine months. There was a correlation between shedding and antibody titre but the cats could remain seropositive for some time after they had ceased shedding virus. One-off testing for FCoV by RT-PCR is inappropriate. Identification of longterm carriers requires that a positive result be obtained by RT-PCR on faecal samples for at least eight consecutive months. A cat should be shown to be negative over five months, or to have become seronegative, to ensure that it has ceased shedding virus.
Vet Rec 2001 May 26
PMID:Use of a reverse-transcriptase polymerase chain reaction for monitoring the shedding of feline coronavirus by healthy cats. 1140 Sep 84

In a case-control study of the infectious agents associated with natural outbreaks of respiratory disease in pheasants, 28 batches of birds from sites affected by disease and eight batches of birds from unaffected sites were examined by six veterinary laboratories in England, Wales and Scotland, and tested for mycoplasmas, other bacteria and viruses. Sinusitis was the commonest sign of disease and was associated with Mycoplasma gallisepticum as detected by PCR in the trachea (P < 0.05) and conjunctiva (P < 0.01). Sinusitis was also associated with pasteurella cultured from the sinus (P < 0.05), antibody to avian pneumovirus (APV) (P < 0.01) and avian coronaviruses as detected by reverse-transcriptase PCR (P < 0.05); there was no association between disease and APV as detected by PCR. Avian coronaviruses were the most common infectious agents detected. They were genetically close to infectious bronchitis virus (IBV) but differed in their gene sequence from all the serotypes of IBV previously identified in domestic fowl, and serological tests with six known IBV types showed little cross reactivity. Mycoplasma species other than M gallisepticum were cultured in 18 batches of pheasants but, with the exception of Mycoplasma gallinaceum, were not associated with disease.
Vet Rec 2002 May 25
PMID:Infectious agents associated with respiratory disease in pheasants. 1205 35


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