Showing papers on "RNA published in 1972"
TL;DR: The observed concatemers of T7 DNA are consistent with replication schemes resulting in double-helical molecules with 3´ ended tails as discussed by the authors, and they can then join to form dimers which on further replication similarly form larger concatures.
Abstract: The observed concatemers of T7 DNA are consistent with replication schemes resulting in double-helical molecules with 3´ ended tails. Right-ended and left-ended molecules can then join to form dimers which on further replication similarly form larger concatemers.
1,409 citations
TL;DR: By characterization of fragments, isolated from a nuclease digest of MS2 RNA, the entire nucleotide sequence of the coat gene was established and a “flower”-like model is proposed for the secondary structure.
Abstract: By characterization of fragments, isolated from a nuclease digest of MS2 RNA, the entire nucleotide sequence of the coat gene was established. A “flower”-like model is proposed for the secondary structure. The genetic code makes use of 49 different codons to specify the sequence of the 129 amino-acids long coat polypeptide.
476 citations
TL;DR: It is demonstrated that transfer RNA of both Escherichia coli and Xenopus laevis is made up from 30 to 40 basic nucleotide sequences distinguishable by RNA-DNA hybridization and are therefore highly conserved in these species.
366 citations
TL;DR: Daunomycin, a glycosidic anthracycline antibiotic from Streptomyces peucetius, is being used in the treatment of acute leukaemia and solid tumours in man due to complex formation with the DNA of deoxyribonucleoprotein4.
Abstract: DAUNOMYCIN1–3, a glycosidic anthracycline antibiotic from Streptomyces peucetius4, is being used in the treatment of acute leukaemia and solid tumours in man5,6. The biological activity seems to be due to complex formation with the DNA of deoxyribonucleoprotein4. In vivo, daunomycin inhibits both RNA and DNA synthesis7,8 and, in vitro, DNA-dependent RNA polymerase and DNA polymerase7–9.
355 citations
TL;DR: The histone messenger RNA in HeLa cells does not contain the large poly(A) segment found in the majority of mRNA molecules, and the exit time from nucleus to cytoplasm is less for histone mRNA than for the generality of mRNA.
340 citations
TL;DR: The contention that all eukaryotes synthesize ribosomes similarly and that yeast may be a useful organism for the investigation of intracellular communication, particularly across the nuclear membrane is supported.
339 citations
TL;DR: Results presented here show that the labeled RNA which does reach polysomes in the presence of 3′deoxyadenosine can be characterized as messenger RNA which contains smaller poly(A) segments than normal messenger RNA.
321 citations
306 citations
TL;DR: In the course of purifying RNase P, it is discovered in other subcellular fractions of E. coli RNase activities potentially responsible for additional steps of precursor tRNA processing.
297 citations
TL;DR: 5-Hydroxymethylcytosine is demonstrable in mouse and frog brain DNA and in the crude cytidylic acid fractions obtained from RNA hydrolysates of rat brain and liver and by its conversion into 5-hydroxym methyluracil.
Abstract: A method is given for small-scale preparation of DNA from 1.0–1.5g of adult rat tissues. The product from brain or liver is characterized by base ratios and phosphorus content which accord with reported values for rat tissue. It is reasonably free of RNA, protein and glycogen. It contains 5-hydroxymethylcytosine at a content of about 15% of the total cytosine bases present. 5-Hydroxymethylcytosine is also demonstrable in mouse and frog brain DNA and in the crude cytidylic acid fractions obtained from RNA hydrolysates of rat brain and liver. 5-Hydroxymethylcytosine is identified by paper chromatography, u.v. spectra in acid and alkaline solutions and by its conversion into 5-hydroxymethyluracil.
293 citations
TL;DR: This work has measured the stability of mRNA in exponentially growing mouse L-cells without having to resort to the use of inhibitors of RNA synthesis, and found that poly A-containing mRNA has a half-life of 10 h, and thus turns over approximately once per cell generation (15 h).
Abstract: THE discovery that messenger RNA (mRNA) in mammalian cells contains sequences of polyadenylic acid (poly A) about 200 nucleotides long localized at the 3′-OH terminus of the mRNA molecule1–5 has raised questions about the function of poly A, but has also provided a powerful new tool for the study of mRNA metabolism. I have measured the stability of mRNA in exponentially growing mouse L-cells without having to resort to the use of inhibitors of RNA synthesis, and found that poly A-containing mRNA has a half-life of 10 h, and thus turns over approximately once per cell generation (15 h). This high stability is in striking contrast to the 3–4 h half-life for mRNA in cultured cells obtained by following the decay of polyribosomes after treatment with a high dose of actinomycin D6,7, This, however, agrees with the finding of Cheevers and Sheinin8 that there is a long-lived fraction of mRNA in cells treated with a low dose of actinomycin D. Singer and Penman9 have simultaneously found that poly A-containing mRNA in HeLa cells turns over about once per cell generation.
TL;DR: Cells producing Rous sarcoma virus contain virus-specific ribonucleic acid (RNA) which can be identified by hybridization to single-stranded deoxyribonucleics acid (DNA) synthesized with RNA-directed DNA polymerase, and the hybrids formed have a high order of thermal stability.
Abstract: Cells producing Rous sarcoma virus contain virus-specific ribonucleic acid (RNA) which can be identified by hybridization to single-stranded deoxyribonucleic acid (DNA) synthesized with RNA-directed DNA polymerase. Hybridization was detected by either fractionation on hydroxyapatite or hydrolysis with single strand-specific nucleases. Similar results were obtained with both procedures. The hybrids formed between enzymatically synthesized DNA and viral RNA have a high order of thermal stability, with only minor evidence of mismatched nucleotide sequences. Virus-specific RNA is present in both nuclei and cytoplasm of infected cells. This RNA is remarkably heterogeneous in size, including molecules which are probably restricted to the nucleus and which sediment in their native state more rapidly than the viral genome. The nature of the RNA found in cytoplasmic fractions varies from preparation to preparation, but heterogeneous RNA (ca. 4-50S), smaller than the viral genome, is always present in substantial amounts.
TL;DR: SCIENCE is published weekly, except the last week in December, but with an extra issue on the third Tuesday in November, by the American Association for the Advancement Science, 1515 Massachusetts Ave., NW, Washington, D.C. 20005.
Abstract: SCIENCE is published weekly, except the last week in December, but with an extra issue on the third Tuesday in November, by the American Association for the Advancement Science, 1515 Massachusetts Ave., NW, Washington, D.C. 20005. Now combined with The Scientific Monthly. Second-class postage paid at Washington, D.C. Copyright t 1972 the American Association for the Advancement of Science. Annual subscription $20; foreign postage: Americas $3; overseas $5; 'air freight to Europe, North Africa, Near East $ single copies $1 (back issues, $2) except Guide to Scientific Instruments which is $4. School year subscription: 9 months, $15; 10 mnh,$67,Poide 4 weeks notice change of address, giving new and old address and zip codes. Send a recent address label. SCIENCE is indexed in the Reader's Guide to Periodical LIteature. EDITORIAL
TL;DR: Results as well as the analysis of minor components of RNase T 1 digest and the oligonucleotides produced by pancreatic RNase have unequivocally identified this RNA as the fibroin mRNA.
TL;DR: An RNA methylase activity, absent from resistant strains, is shown here to methylate in vitro the 16S RNA of resistant as well as sensitive strains.
Abstract: Strains of Escherichia coli are resistant to the antibiotic kasugamycin due to the partial non-methylation of 16S ribosomal RNA. An RNA methylase activity, absent from resistant strains, is shown here to methylate in vitro the 16S RNA of resistant as well as sensitive strains.
TL;DR: Rifampicin does not block synthesis of the replicative forms of varphiX174 either in vivo or in soluble extracts, and DNA synthesis with deoxyribonucleoside triphosphates and a fresh addition of enzymes is not required.
Abstract: Soluble enzyme fractions from uninfected Escherichia coli convert M13 and ϕX174 viral single strands to their double-stranded replicative forms. Rifampicin, an inhibitor of RNA polymerase, blocks conversion of M13 single strands to the replicative forms in vivo and in vitro. However, rifampicin does not block synthesis of the replicative forms of ϕX174 either in vivo or in soluble extracts. The replicative form of M13 synthesized in vitro consists of a full-length, linear, complementary strand annealed to a viral strand. The conversion of single strands of M13 to the replicative form proceeds in two separate stages. The first stage requires enzymes, ribonucleoside triphosphates, and single-stranded DNA; the reaction is inhibited by rifampicin. The macromolecular product separated at this stage supports DNA synthesis with deoxyribonucleoside triphosphates and a fresh addition of enzymes; ribonucleoside triphosphates are not required in this second stage nor does rifampicin inhibit the reaction. We presume that in the first stage there is synthesis of a short RNA chain, which then primes the synthesis of a replicative form by a DNA polymerase.
TL;DR: It is suggested that ribosomal RNA is synthesized by form I, the major α-amanitin-resistant RNA polymerase found in these nuclei, but cannot rule out the possible involvement of form III, a minor α-Manatin-resistantRNA polymerase which is also present.
TL;DR: Subunit III is shown to be identical to the protein synthesis elongation factor EF Tu by the following criteria: coelectrophoresis on sodium dodecyl sulfate gels, precipitation ofEF Tu by anti-Qbeta replicase serum, binding of guanine nucleotides, and binding of phenylalanyl-tRNA.
Abstract: The enzyme, Qbeta replicase, responsible for the replication of the RNA of Escherichia coli pahge Qbeta, is composed of four nonidentical subunits, three of which, I, III, and IV, are coded for by the bacterial genome, while subunit II is phage-specific. SUBUNIT IV IS SHOWN TO BE IDENTICAL TO THE PROTEIN SYNTHESIS ELONGATION FACTOR EF TS BY THE FOLLOWING CRITERIA: coelectrophoresis on polyacrylamide gels in sodium dodecyl sulfate and in urea buffers, identity of the first seven amino acids at the amino-terminus, precipitation of sub-unit IV by anti-EF T-factor serum, and stimulation of EF Tu-GDP exchange by subunit IV. Subunit III is shown to be identical to the protein synthesis elongation factor EF Tu by the following criteria: coelectrophoresis on sodium dodecyl sulfate gels, precipitation of EF Tu by anti-Qbeta replicase serum, binding of guanine nucleotides, and binding of phenylalanyl-tRNA. In addition, Qbeta replicase activity can be reconstituted from subunits I and II with EF Tu and EF Ts.
TL;DR: Molecular hybridization with radioactive polyuridylic acid has been used to detect regions of polyadenylic acid in virus RNA to make a qualitative distinction between RNA preparations from the two virus classes.
Abstract: Molecular hybridization with radioactive polyuridylic acid has been used to detect regions of polyadenylic acid in virus RNA. On the average, RNA from tumour viruses is twenty-five to fifty-fold richer in polyadenylic acid than RNA from non-oncogenic viruses. Polyacrylamide gel electrophoresis permitted a qualitative distinction between RNA preparations from the two virus classes.
TL;DR: The isolation of a replicating RNA molecule that contains 218 nucleotides and possesses the other features desired for a definitive analysis of the replicating mechanism will permit the precise identification of the base changes required to mutate from one phenotype to another in the course of extracellular Darwinian selection experiments.
Abstract: The aim of the present study is to make available a replicating molecule of known sequence. Accordingly, we sought a molecule that has the following properties: (a) replicates in vitro in a manner similar to phage Qβ RNA; (b) produces antiparallel complementary strands that can be separated from one another; and (c) is small enough to yield its sequence with reasonable effort.
We report here the isolation of a replicating RNA molecule that contains 218 nucleotides and possesses the other features desired for a definitive analysis of the replicating mechanism. Despite its small size, this molecule can mutate to previously determined phenotypes. It will, therefore, permit the precise identification of the base changes required to mutate from one phenotype to another in the course of extracellular Darwinian selection experiments.
TL;DR: The data establish that YpGPGp(Ap)(n)A(OH) is the 3'-terminal sequence of poliovirus RNA, Type 1 (Mahoney), which may modify prior interpretations of the function of polyadenylate ends on messenger RNAs.
Abstract: Poliovirus RNA that has been derivatized at the 3′-end with NaIO4-NaB3H4 yields, after hydrolysis with alkali or RNase T2, predominantly labeled residues of modified adenosine; no labeled nucleoside derivative is produced by digestion with RNase A or RNase T1. The 3′-terminal bases of the RNA are, therefore,...ApAOH. Hydrolyzates of poliovirus [32P]RNA, after exhaustive digestion with RNase T1 or RNase A, contain, besides internal oligonucleotides, polynucleotides resistant to further action of ribonucleases T1 and A, respectively; these polynucleotides were isolated by membrane-filter binding or ion-exchange chromatography. The sequence of the T1-resistant polynucleotide was determined to be (Ap)nAOH, that of the RNase A-resistant polynucleotide was GpGp(Ap)nAOH. The chain length (n) of the polyadenylic acid, as analyzed by different methods, averages 89 nucleotides. Gel electrophoresis revealed heterogeneity of the size of poly(A). Poliovirus RNA, when labeled in vitro at the 3′-end, contains [3′-3H]poly(A); when labeled in vivo with [3H]A, it contains [3H](Ap)nAOH. The data establish that... YpGpGp(Ap)[unk]AOH is the 3′-terminal sequence of poliovirus RNA, Type 1 (Mahoney). Since this mammalian virus reproduces in the cell cytoplasm, these observations may modify prior interpretations of the function of polyadenylate ends on messenger RNAs.
TL;DR: A cloned line of murine proerythroblastoid cells (T-3-Cl-2), transformed by Friend leukemia virus, undergoes changes associated with erythroid differentiation when treated with dimethylsulfoxide in culture, and hybridizable cytoplasmic RNA induced in these cells has the sedimentation properties of 9S globin mRNA.
Abstract: A cloned line of murine proerythroblastoid cells (T-3-Cl-2), transformed by Friend leukemia virus, undergoes changes associated with erythroid differentiation when treated with dimethylsulfoxide in culture This line, which does not undergo spontaneous differentiation, develops specific erythrocyte-membrane antigen and accumulates detectable amounts of heme within four days of dimethylsulfoxide treatment In the present study, we have followed the phenotypic expression of the globin genes by measuring globin mRNA in differentiating cells Our hybridization probe for this purpose is [3H]DNA, which is complementary to purified globin mRNA, synthesized by viral RNA-directed DNA polymerase This probe is sufficiently sensitive to detect less than 1 ng of globin mRNA Using it, we find little or no hybridizable globin mRNA in either uninduced cells or in treated control lymphoid cells In contrast, globin mRNA can be detected in T-3-Cl-2 cell 2 days after induction by dimethylsulfoxide; it reaches a maximum concentration four days after induction At this time, cells that stain positively for heme appear The hybridizable cytoplasmic RNA induced in these cells has the sedimentation properties of 9S globin mRNA Considering the stable character of globin mRNA, our results are most readily explained in terms of a transcriptional activation of the globin genes
TL;DR: It was demonstrated that actinomycin D at low concentration, 0.04 μg/ml, supresses the appearance of mRNA on polysomes to an extent of 50%.
Abstract: Messenger RNA from polysomes of KB-cells was isolated by affinity chromatography on columns of polyuridylic acid covalently linked to Sepharose. The mRNA molecules were retained by the resin apparently via their poly(A) segments by base pairing to the poly(U). Ribosomal RNA and transfer RNA were not retained by the columns and were thus removed from the mRNA. The mRNA was recovered to an extent of 90% and apparently in intact form.
This method allows studies of mRNA resulting from unabated synthesis and was used here in studies of the size distribution of different classes of cytoplasmic poly(A)-containing RNA. The presence of poly(A)-containing RNA in the non-polysomal fractions of the cytoplasm was demonstrated. This putative mRNA was shown to constitute about 30% of the total cytoplasmic poly(A)-containing RNA. Also by using the poly (U)-Sepharose technique it was demonstrated that actinomycin D at low concentration, 0.04 μg/ml, supresses the appearance of mRNA on polysomes to an extent of 50%. This low concentration of the drug was previously though to effect only ribosomal RNA synthesis.
TL;DR: ADENYLIC ACID (A)-rich sequences have been found in some mRNAs of animal cells1,2 and DNA viruses3 but not in the RNAs of cytocidal or oncogenic RNA viruses.
Abstract: ADENYLIC ACID (A)-rich sequences have been found in some mRNAs of animal cells1,2 and DNA viruses3 but not in the RNAs of cytocidal or oncogenic RNA viruses These sequences have been proposed to be involved in the transport of mRNA to the cytoplasm from the nucleus or vaccinia virus core2,3, or in the association of mRNA with proteins necessary for translation1
TL;DR: It is shown that mRNA decay is not responsible for protein synthesis decay in actinomycin, and therefore, mRNA appears quite stable after the administration of act inomycin.
Abstract: SYNTHESIS of proteins from the mRNA in eukaryotic cells differs from prokaryotes in two important ways. In the mammalian cell, the translation of mRNA in the cytoplasm is remote from the transcription in the nucleus, whereas in bacteria these two processes occur almost simultaneously1,2. Bacterial protein synthesis ceases within several minutes of inhibition of RNA transcription with actinomycin3; hence, the mRNA is short-lived. In metazoan eukaryotic cells, a similar experiment indicates that protein synthesis is not immediately affected by inhibition of transcription. Thus the mRNA is much more stable—of the order of several hours4. In a few specialized systems, the lifetime of mRNA can be deduced by observing the decay of protein synthesis after RNA synthesis has ceased. The messenger for haemoglobin in the reticulocyte5 and for silk fibroin in the silkworm6 are examples of stable messenger molecules with a lifetime of several days. The measurement of messenger lifetime in cells with active RNA metabolism is more difficult. In the experimental approach mentioned above, new RNA synthesis was blocked with actinomycin and the subsequent decay of protein synthesis measured. Under these conditions, protein synthesis generally decreased with a 2.5 to 3 h half-life in a wide variety of systems4,7–9. Interpreting the decay of protein synthesis as due to a concomitant degradation of mRNA assumes that the availability of messenger molecules is limiting in protein synthesis. Here, we shall show that mRNA decay is not responsible for protein synthesis decay in actinomycin. Rather, mRNA appears quite stable after the administration of actinomycin. The subsequent decay of protein synthesis appears to be due to a failure in the initiation of translation.
TL;DR: A human cervical tumor, free of detectable infectious herpes simplex 2 virus, contained a fragment comprising 39% of herpes viral DNA, which is considerably less than that transcribed in productively infected cells.
Abstract: A human cervical tumor, free of detectable infectious herpes simplex 2 virus, contained a fragment comprising 39% of herpes viral DNA. Renaturation kinetics indicate that an average of 1 to 3.5 DNA fragments of herpes simplex virus are present per cell, depending on the ploidy of the cells in this particular tumor. Virus-specific sequences were found linked to highly repetitive sequences of host DNA, which reassociated under conditions designed to preclude reassociation of viral sequences. The tumor also contained RNA transcripts complementary to 5% of the viral DNA. The fraction of viral DNA template transcribed in the cervical tumor is considerably less than that transcribed in productively infected cells (50%).
TL;DR: The following two articles describe successful syntheses in vitro of DNA copies of various mammalian globin mRNAs, using reverse transcriptase from avian myoblastosis virus, using poly(dT) sequences at their 3′-ends.
Abstract: The following two articles describe successful syntheses in vitro of DNA copies of various mammalian globin mRNAs, using reverse transcriptase from avian myoblastosis virus. Short stretches of poly(dT) greatly enhance this effect, presumably because they prime correct initiation of reverse transcription of these mRNAs by pairing with known poly (A) sequences at their 3′-ends.
TL;DR: A bacterial protein required for the replication of bacteriophage Qβ RNA in vitro has been purified from uninfected Escherichia coli to apparent homogeneity and studies on the role of factor suggest that this host protein acts as a positive control element required at some step prior to the initiation of synthesis with Q β RNA template.
TL;DR: This chapter focuses on the structure and synthesis of transfer RNA (tRNA) and discusses the biochemistry of tRNA methylases, a complex family of enzymes that modify the structure of preformed tRNA by the insertion of methyl groups into specific positions in the four main bases of t RNA.
Abstract: Publisher Summary This chapter focuses on the structure and synthesis of transfer RNA (tRNA) and discusses the biochemistry of tRNA methylases. Translation is the most complex molecular mechanism known in the living cell. It requires messenger RNA, which is the simplest of the structures involved, even though it is laden with information. The ribosomes are complex structures composed of RNA and at least a score of different proteins. Transfer RNA is the most complex biomacromolecule known. In addition to these major components, there are ancillary ones— enzymes that transfer amino acids to the transfer RNA. Moreover, there are at least 8 soluble protein factors needed for the completion of the synthesis of a protein. Any or all of these numerous components could be a regulatory factor in protein synthesis. There are three different lines of biological evidence that point to transfer RNA as a regulatory factor. Transfer RNA is a pivotal molecule in protein synthesis. It is the link between the amino acids and the message-bearing nucleic acids. The tRNA methylases are a complex family of enzymes that modify the structure of preformed tRNA by the insertion of methyl groups into specific positions in the four main bases of tRNA. The enzymes are species-specific, organ-specific, base-specific, and even site-specific for particular bases.