scispace - formally typeset
Search or ask a question

Showing papers on "RNA-dependent RNA polymerase published in 1970"


Journal ArticleDOI
27 Jun 1970-Nature
TL;DR: Two independent groups of investigators have found evidence of an enzyme in virions of RNA tumour viruses which synthesizes DNA from an RNA template, apparently the classical process of information transfer from DNA to RNA can be inverted.
Abstract: Two independent groups of investigators have found evidence of an enzyme in virions of RNA tumour viruses which synthesizes DNA from an RNA template. This discovery, if upheld, will have important implications not only for carcinogenesis by RNA viruses but also for the general understanding of genetic transcription: apparently the classical process of information transfer from DNA to RNA can be inverted.

1,872 citations


Journal ArticleDOI
27 Jun 1970-Nature
TL;DR: Viral RNA-dependent DNA Polymerase: RNA- dependent DNA polymerase in Virions of Rous Sarcoma Virus and its role in cell reprograming is studied.
Abstract: Viral RNA-dependent DNA Polymerase: RNA-dependent DNA Polymerase in Virions of Rous Sarcoma Virus

1,833 citations


Journal ArticleDOI
23 Oct 1970-Science
TL;DR: α-Amanitin, a toxic substance from the mushroom Amanita phalloides, is a potent inhibitor of DNA-dependent RNA polymerase II (the nucleoplasmic form) from sea urchin, rat liver, and calf thymus.
Abstract: alpha-Amanitin, a toxic substance from the mushroom Amanita phalloides, is a potent inhibitor of DNA-dependent RNA polymerase II (the nucleoplasmic form) from sea urchin, rat liver, and calf thymus. This compound exerts no effect on the activity of polymerase I (nucleolar form) or polymerase III (also nucleoplasmic). The inhibition is due to a specific interaction with polymerase II or with a complex of DNA and polymerase II.

792 citations



Journal ArticleDOI
17 Oct 1970-Nature
TL;DR: A new T7-specific RNA polymerase is found in T7 phage-infected cells and provides a direct explanation for the pleiotropic control of late T7 functions exerted by gene I.
Abstract: A new T7-specific RNA polymerase is found in T7 phage-infected cells It is the product of T7 gene I and is physically and biochemically distinct from the host cell RNA polymerase The synthesis of T7 RNA polymerase provides a direct explanation for the pleiotropic control of late T7 functions exerted by gene I

576 citations


Journal ArticleDOI
TL;DR: α-amanitin selectively inhibits RNA synthesis catalyzed by calf thymus RNA polymerase activity B by interacting with the enzyme and inhibiting chain elongation as discussed by the authors, which can be used to identify the source of RNA synthesis.

449 citations


Journal ArticleDOI
TL;DR: The virions of vesicular stomatitis virus contain an enzyme that catalyzes the incorporation of ribonucleotides into RNA, and the product of the reaction is mainly RNA complementary in base sequence to that of veS virus RNA.
Abstract: The virions of vesicular stomatitis virus contain an enzyme that catalyzes the incorporation of ribonucleotides into RNA. The product of the reaction is mainly RNA complementary in base sequence to that of vesicular stomatitis virus RNA.

365 citations


Journal ArticleDOI
08 Aug 1970-Nature
TL;DR: Several RNA tumour viruses contain an enzyme that synthesizes a DNA–RNA hybrid using the single stranded viral RNA as template, and hybridization experiments confirm that the DNA strand is complementary to the viral RNA.
Abstract: Several RNA tumour viruses contain an enzyme that synthesizes a DNA–RNA hybrid using the single stranded viral RNA as template. Hybridization experiments confirm that the DNA strand is complementary to the viral RNA.

261 citations


Journal ArticleDOI
05 Dec 1970-Nature
TL;DR: An RNA dependent DNA polymerase analogous to that of RNA tumour viruses has been found in lymphoblasts of leukaemic patients but not of normal donors.
Abstract: An RNA dependent DNA polymerase analogous to that of RNA tumour viruses has been found in lymphoblasts of leukaemic patients but not of normal donors. The enzyme can use an RNA template from mammalian cells to synthesize DNA.

240 citations


Journal ArticleDOI
TL;DR: The results suggest that messenger RNA and nuclear heterogeneous RNA are synthesized separately, and that the transcription of messenger RNA is inhibited by the drug.
Abstract: Cordycepin (3′-deoxyadenosine) suppresses the labeling of messenger RNA in HeLa cells. The drug has no effect on either the labeling of nuclear heterogeneous RNA or on the transport of messenger RNA into the cytoplasm. The results suggest that messenger RNA and nuclear heterogeneous RNA are synthesized separately, and that the transcription of messenger RNA is inhibited by the drug.

235 citations



Journal ArticleDOI
TL;DR: It is shown that formaldehyde-treated RNA initiates synthesis as well of at least three polypeptides which do not correspond to any known f2 genes, implying that there are several nucleotide sequences on f2 RNA which could initiate protein synthesis but are normally prevented from doing so by the RNA structure.

Journal ArticleDOI
01 Dec 1970-Virology
TL;DR: The finding of multiple pieces of messenger RNA, all smaller than 40 S virion RNA, suggests that VSV polypeptides are synthesized from individual molecules of RNA, rather than from one large messenger RNA.


Journal ArticleDOI
01 Dec 1970-Virology
TL;DR: The results of reconstruction experiments suggest that the viral 4 S RNA is not simply a contaminant derived from cellular debris, and are in accord with previous suggestions that RNA tumor viruses contain tRNA acquired from the host cell during assembly.

Journal ArticleDOI
07 Nov 1970-Nature
TL;DR: The RNA replicating enzyme induced by RNA phage Qβ consists of a single phage specific and three host specific polypeptide chains, and none are known subunits of E. coli DNA-dependent RNA polymerase.
Abstract: The RNA replicating enzyme induced by RNA phage Qβ consists of a single phage specific and three host specific polypeptide chains. At least one of the host subunits is shown to be essential for enzymatic activity, and none are known subunits of E. coli DNA-dependent RNA polymerase.

Journal ArticleDOI
31 Oct 1970-Nature
TL;DR: Six RNA viruses have now been shown to contain DNA polymerase activities directed by single-stranded RNA, double-Stranded RNA and double-stranding DNA, and it is further demonstrated that DNA–RNA hybrids, such as synthetic dC.rG, act as even more effective templates.
Abstract: Six RNA viruses have now been shown to contain DNA polymerase activities directed by single-stranded RNA, double-stranded RNA and double-stranded DNA. It is further demonstrated that DNA–RNA hybrids, such as synthetic dC.rG, act as even more effective templates.

Journal ArticleDOI
TL;DR: Messenger RNA synthesis and release by vaccinia subviral particles (cores) was studied in vitro using in part a nitrocellulose filter binding assay for the detection of core-bound, nascent messenger RNA.

Journal ArticleDOI
24 Oct 1970-Nature
TL;DR: Preliminary results of an enquiry into the effects of the imprinting stimulus on the activity of RNA polymerase in three regions of the chick's brain are presented.
Abstract: EXPOSURE to an imprinting stimulus has been shown to be associated with an increase in incorporation rates of lysine into protein and uracil into RNA in the forebrain roof in one-day-old chicks' brains1,2. A maximum increase in RNA incorporation is seen at 76 min after the start ofthe imprinting procedure and in protein incorporation at 120 min. Studies of the changes occurring in other protein synthesizing systems in response to external stimuli such as hormones have demonstrated a similar type of temporal sequence for the protein and RNA changes. In hormonal systems one of the events preceding both of these is an increase in RNA polymerase activity3. It seemed reasonable to test whether such an effect also occurs during imprinting in the chick. We present here preliminary results of an enquiry into the effects of the imprinting stimulus on the activity of RNA polymerase in three regions of the chick's brain.

Journal ArticleDOI
TL;DR: Twenty-three temperature-sensitive mutants of Saccharomyces cerevisiae, all of which undergo a rapid cessation of net RNA accumulation following a shift from the permissive to the restrictive temperature, are characterized and ten genes are defined that play an essential role in the formation or maturation of ribosomes in yeast.
Abstract: Twenty-three temperature-sensitive mutants of Saccharomyces cerevisiae, all of which undergo a rapid cessation of net RNA accumulation following a shift from the permissive (23°) to the restrictive temperature (36°), have been characterized. Genetic studies demonstrate that these mutants belong to ten different complementation groups and that, in most cases, their properties are the result of a single, recessive mutation in a nuclear gene. Although the mutants were isolated for heat sensitivity, mutants from 2 of the complementation groups are cold sensitive (at 13°) as well. The mutants continue to synthesize protein, including an enzyme, alkaline phosphatase, for two to four hours following a shift from 23° to 36°, suggesting that they are capable of messenger RNA synthesis and the translation of messenger RNA with fidelity at the restrictive temperature. The small amount of RNA that is synthesized in these mutants at the restrictive temperature has been examined on sucrose gradients and by acrylmide gel electrophoresis; in addition, the RNA components in polyribosomes have been fractionated by a new technique that separates messenger RNA from ribosomal RNA. As a result of these analyses we conclude that these mutants are strongly inhibited in the accumulation of 5S, 7S, 17S, and 25S RNA components but are only slight if at all inhibited in the synthesis of messenger RNA and 4S RNA. The results reported here define ten genes, designated rna 2 through rna 11, that play an essential role in the formation or maturation of ribosomes in yeast.

Journal ArticleDOI
29 Aug 1970-Nature
TL;DR: RNA polymerase from sporulating cells of B. subtilis has a subunit structure different from the vegetative enzyme, which may be responsible for the turn-off of vegetative genes during spore formation.
Abstract: RNA polymerase from sporulating cells of B. subtilis has a subunit structure different from the vegetative enzyme. This alteration of RNA polymerase may be responsible for the turn-off of vegetative genes during spore formation.

Journal ArticleDOI
05 Sep 1970-Nature
TL;DR: Besides having RNA-dependentDNA polymerase activity, oncogenic RNA viruses possess a DNA-directed DNA polymerase which is distinguished from previously described enzymes of this type in preferring double-stranded DNA as template and yielding a principally double-Stranded product.
Abstract: Besides having RNA-dependent DNA polymerase activity, oncogenic RNA viruses possess a DNA-directed DNA polymerase which is distinguished from previously described enzymes of this type in preferring double-stranded DNA as template and yielding a principally double-stranded product.


Journal ArticleDOI
21 Nov 1970-Nature
TL;DR: A transcription factor, Ψr, which preferentially stimulates the synthesis of ribosomal RNA in vitro has been identified in crude extracts of E. coli and is also a component of Qβ replicase.
Abstract: A transcription factor, Ψ r , which preferentially stimulates the synthesis of ribosomal RNA in vitro has been identified in crude extracts of E. coli. This factor activity is also a component of Qβ replicase.

Journal ArticleDOI
27 Jun 1970-Nature
TL;DR: In the presence of σ, E. coli RNA polymerase forms rifampicin resistant complexes with DNA in the absence of nucleoside triphosphates, so the number of ρ-recognized promoters per genome for several DNA phages could be determined.
Abstract: In the presence of σ, E. coli RNA polymerase forms rifampicin resistant complexes with DNA in the absence of nucleoside triphosphates. These complexes only form at promoter sites, so the number of σ-recognized promoters per genome for several DNA phages could be determined.

Journal ArticleDOI
TL;DR: It is inferred that both in mouse and Drosophila the centromeric regions of all chromosomes are enriched in highly reiterated sequences, which might play some role in promoting the close physical approximation of homologous and non-homologous chromosomes or chromosome regions to facilitate regulation of function.
Abstract: The location of highly reiterated nucleotide sequences on the chromosomes has been studied by the technique of in situ hybridisation between the DNA of either Drosophila melanogaster salivary gland chromosomes or mouse chromosomes and tritium labelled complementary RNA (c-RNA) transcribed in vitro from appropriate templates with the aid of DNA dependent RNA polymerase extracted from Micrococcus lysodeikticus. The location of the hybrid material was identified by autoradiography after RNase treatment. — When Drosophila c-RNA, transcribed from whole DNA, was annealed with homologous salivary chromosomes in the presence of formamide the well defined labelling was confined to the chromocentre. With heat instead of formamide denaturation there was evidence of discontinuous labelling in various chromosome regions as well, apparently associated with banding. Xenopus ribosomal RNA showed no evidence of annealing to Drosophila chromosomes with the comparatively short exposure times used here. — When mouse satellite DNA was used as template the resulting c-RNA showed no hybridisation to Drosophila chromosomes but, when annealed with mouse chromosomes, the centromeric regions were intensely labelled. The interphase nuclei showed several distinct regions of high activity which suggested aggregation of centromeric regions of both homologous and non-homologous chromosomes. The results of annealing either c-RNA or labelled satellite DNA to homologous chromosomes were virtually indistinguishable. Incubation of Drosophila c-RNA with mouse chromosomes provided no evidence of localisation of grains. — It is inferred that both in mouse and Drosophila the centromeric regions of all chromosomes are enriched in highly reiterated sequences. This may be a general phenomenon and it might be tentatively suggested that the highly reiterated sequences play some role in promoting the close physical approximation of homologous and non-homologous chromosomes or chromosome regions to facilitate regulation of function.

Journal ArticleDOI
03 Jan 1970-Nature
TL;DR: MOST inhibitors of RNA synthesis act on the DNA template rather than directly on the polymerizing enzyme, so the bacterial polymerase but not the animal polymerase is inhibited by the rifamycins11, streptovaricin12 and probably streptolydigin13.
Abstract: MOST inhibitors of RNA synthesis act on the DNA template rather than directly on the polymerizing enzyme. Antibiotics that inhibit RNA synthesis by binding to DNA include actinomycin D1, miracil D2, nogalomycin3, chromomycin A34, aflatoxin5, echinomycin, daunomycin, mithramycin and olivomycin6, ethidium bromide7, pro-flavine8, nitrogen mustard9 and acetylaminofluorene10. In each case tested, there is evidence that the antibiotic can inhibit RNA synthesis in both animal and bacterial cells, a finding to be expected because the site of the inhibitory action is the DNA template and not the enzyme. On the other hand, a few antibiotics are known to react with the enzyme molecule itself and these are more species selective. The bacterial polymerase but not the animal polymerase is inhibited by the rifamycins11, streptovaricin12 and probably streptolydigin13. Rifamycin has been shown to bind stoichiometrically to the bacterial enzyme molecule and to prevent initiation14, whereas streptolydigin appears to inhibit chain elongation13.

Journal ArticleDOI
01 Sep 1970-Virology
TL;DR: The hydrodynamic properties and the components of membrane-associated virus-specific structures isolated from the cytoplasm of poliovirus-infected HeLa cells have been determined and suggest a model for the membrane- associated replication and translation of viral RNA.

Journal ArticleDOI
TL;DR: A soluble RNA-dependent DNA polymerase activity has been released from murine leukemia particles in the presence of manganese and high detergent concentrations.
Abstract: The RNA-dependent DNA polymerase(s) in murine leukemia, murine mammary tumor, and avian myeloblastosis viruses require maganese for optimal activity. The transcription of added synthetic polyribonucleotides is greatly enhanced when manganese is used in place of magnesium. A soluble RNA-dependent DNA polymerase activity has been released from murine leukemia particles in the presence of manganese and high detergent concentrations. Two RNA viruses, visna virus of sheep and a primate syncytial virus, not known to have tumor-producing ability, also contain the polymerase.

Journal ArticleDOI
TL;DR: The binary complex between RNA polymerase containing sigma factor and sigma specific DNA is more rapidly inactivated during prolonged incubation with rifampicin than a complex formed with unspecific DNA or in the absence of sigma.
Abstract: Addition of rifampicin to a preincubated mixture of RNA polymerase and DNA does not lead to inhibition of the subsequent initiation of RNA chain synthesis. The formation of the enzymatically active binary complex between RNA polymerase and DNA, however, proved to be very sensitive to the action of the inhibitor. Once the complex has formed in the absence of substrate the enzyme is resistant to the antibiotic. The presence of sigma factor is not required for the formation of the resistant complex. In the presence of sigma, however, more resistant complex is formed between enzyme and DNA containing sigma specific initiation sites. The binary complex between RNA polymerase containing sigma factor and sigma specific DNA is more rapidly inactivated during prolonged incubation with rifampicin than a complex formed with unspecific DNA or in the absence of sigma. Rifampicin may therefore be used as a tool to discriminate sigma specific and unspecific active complexes of RNA polymerase and template.