Ribonucleic Acid Metabolism Research Articles

Some effects of dexamethasone on nucleic acid metabolism in skin of Merino sheep.

The effects of 8-day intravenous infusions of dexamethasone on deoxyribonucleic and ribonucleic acid metabolism have been examined in the skin of the Merino sheep. In two separate experiments, depilatory doses of dexamethasone (8.4 mg kg-0.75 body weight) were shown to inhibit the [3H]thymidine incorporation into DNA in the skin by about 80%. In the presence of excess thymidine the amount of radioactivity in DNA at the end of infusion decreased to about 50% of the pretreatment values. The incorporation of [3H]uridine into RNA in the skin was not affected. Decreases in the wet weight, DNA and RNA contents of skin were observed at the end of the dexamethasone infusion. In two experiments, wool growth was reduced to 36 +/- 9% (s.e.m.) and 52 +/- 8% of the respective pretreatment values. The results suggest that the dexamethasone caused a reduction in the wool growth by inhibiting DNA biosynthesis of wool follicle cells.

Genome Activity and Gene Expression in Avian Erythroid Cells

Publisher Summary This chapter discusses the genome activity and gene expression in avian erythroid cells. Avian embryogenesis involves at least three generations of erythroid cells, which are (1) the cells of primitive erythropoiesis occurring in the yolk sac, (2) the cells of definitive erythropoiesis in the yolk sac, and (3) the cells of definitive erythropoiesis in the bone marrow. Erythroid cells of different generations differ in morphology, dimensions, the size of the nucleus, and the type of hemoglobin. The functions of the globin genes coding for embryonic and adult globins are switched over at appropriate stages of development by starting a new cell generation rather than intracellularly through modulation of gene activity (repression of the genes for embryonic hemoglobins and activation of the genes for definitive hemoglobins). Analysis of heterogenous nuclear ribonucleic acid (hnRNA) metabolism in differentiating erythroid cells reveals a remarkable feature, the existence of stable hnRNA derivatives in their nuclei. The chapter also describes the possible mechanisms regulating expression of the genes in differentiating avian erythroid cells.

RNA-Helix-Destabilizing Proteins

Publisher Summary This chapter presents a discussion on ribonucleic acid (RNA)-helix-destabilizing proteins. The chapter outlines some aspects of RNA metabolism where the need for helix-destabilizing proteins appears to be evident. The chapter focuses on ribosomal protein S1 from E. coli and protein HD40 from the brine shrimp Artemia salina , a major component of heterogeneous nuclear ribonucleoprotein (hnRNP) particles. In both cases, the in vitro unwinding activity of these proteins can be correlated with their respective functions. The chapter describes the nucleic acid binding and helix-destabilizing properties of protein S1 and HD40. While comparative investigations of analogous proteins from other eukaryotes are needed, HD40 may prove to be a good model for in vitro studies on the structure and function of hnRNP; its physical properties appear to be representative of the glycine-rich core proteins, and it can be purified in relatively large amounts. In contrast to helix-destabilizing proteins participating in dynamic processes that appear to exercise a transient effect on the conformation of the nucleic acid, HD40 is a component of an isolatable nucleoprotein in which the single-stranded RNA is maintained in an unfolded state owing to its interaction with the protein. The chapter recommends the need for in vitro investigations involving purified individual hnRNP proteins and messenger ribonucleic acid (mRNA) precursors along with the development of specific methods for the isolation of native hnRNP.

Association of poly(adenylate)-deficient messenger ribonucleic acid with membranes in mouse kidney.

To describe further the metabolism of messenger ribonucleic acid (mRNA) in mouse kidney, we examined newly synthesized mRNA deficient in poly(adenylate) [poly(A)]. Approximately 50% of renal polysomal mRNA that labeled selectively in the presence of the pyrimidine analogue 5-fluoroorotic acid lacks or is deficient in poly(A) as defined by its ability to bind to poly(A) affinity columns. Nearly one-half of this poly(A)-deficient mRNA is associated uniquely with a cellular membrane fraction detected by sedimentation of renal cytoplasm in sucrose density gradients containing EDTA and nonionic detergents. Poly(A+) mRNA and poly(A)-deficient mRNA [poly(A-) mRNA] have similar modal sedimentation coefficients (20-22 S) and similar cytoplasmic distribution. Although 95% of newly synthesized poly(A+) mRNA is released in 10 mM EDTA as 20-90 S ribonucleoproteins from polysomes greater than 80 S, only 55% of poly(A)-deficient mRNA is released under the same conditions. Poly(A)-deficient mRNA recovered from greater than 80 S ribonucleoproteins resistant to EDTA treatment lacks ribosomal RNA, is similar in size to poly(A+) mRNA, and is associated with membranous structures, since 70% of poly(A)-deficient mRNA in EDTA-resistant ribonucleoproteins is released into the 20-80 S region by solubilizing membranes with 1% Triton X-100. These membrane-associated renal poly(A-) mRNAs could have unique coding or regulatory functions.

Chinese hamster polyadenylated messenger ribonucleic acid: relationship to non-polyadenylated sequences and relative conservation during messenger ribonucleic acid processing.

We have further analyzed the metabolism of specific messenger ribonucleic acid (mRNA) sequences within the cytoplasmic and nuclear RNA of Chinese hamster ovary (CHO) cells by using a set of previously constructed complementary deoxyribonucleic acid (DNA) clones (Harpold et al., Cell 17:1025-1035, 1979) as specific molecular probes in a variety of RNA:DNA hybridization experiments. The majority of the labeled mRNA complementary to each of the nine clones was found in the polyribosomes, with some variation between individual sequences. The great majority of each specific mRNA labeled for 3 h or less was in the polyadenylated [poly(A)+] fraction. However, the amount of each sequence increased in the non-poly(A)+ [poly(A)-] fraction after very long label times, suggesting the derivation of the poly(A)- RNA from the poly(A)+ RNA. Eight of the nine mRNA's have cytoplasmic half-lives ranging from 8 to 14 h, whereas one of the mRNA's, the scarcest in the group, has a somewhat shorter half-life of approximately 3 h. The proportion of each of the specific long-lived mRNA's within the total labeled mRNA increased as a function of labeling time, indicating that a large fraction, probably greater than 50%, of the initially labeled poly(A)+ mRNA in CHO cells has a half-life of less than 3 h. A quantitative analysis of the kinetics of labeling of specific nuclear and cytoplasmic sequences indicated that a significant fraction of the mRNA sequences transcribed from genes containing these nine CHO sequences were successfully processed into mRNA. However, two of the CHO mRNA sequences were only partially conserved during nuclear processing to yield mRNA. These studies demonstrated that events at two post-transcriptional levels, differential nuclear processing efficiency of different primary transcripts and cytoplasmic stability of different mRNA's, can be involved in the determination of the cytoplasmic concentrations of different mRNA's.

Chinese hamster polyadenylated messenger ribonucleic acid: relationship to non-polyadenylated sequences and relative conservation during messenger ribonucleic acid processing.

We have further analyzed the metabolism of specific messenger ribonucleic acid (mRNA) sequences within the cytoplasmic and nuclear RNA of Chinese hamster ovary (CHO) cells by using a set of previously constructed complementary deoxyribonucleic acid (DNA) clones (Harpold et al., Cell 17:1025-1035, 1979) as specific molecular probes in a variety of RNA:DNA hybridization experiments. The majority of the labeled mRNA complementary to each of the nine clones was found in the polyribosomes, with some variation between individual sequences. The great majority of each specific mRNA labeled for 3 h or less was in the polyadenylated [poly(A)+] fraction. However, the amount of each sequence increased in the non-poly(A)+ [poly(A)-] fraction after very long label times, suggesting the derivation of the poly(A)- RNA from the poly(A)+ RNA. Eight of the nine mRNA's have cytoplasmic half-lives ranging from 8 to 14 h, whereas one of the mRNA's, the scarcest in the group, has a somewhat shorter half-life of approximately 3 h. The proportion of each of the specific long-lived mRNA's within the total labeled mRNA increased as a function of labeling time, indicating that a large fraction, probably greater than 50%, of the initially labeled poly(A)+ mRNA in CHO cells has a half-life of less than 3 h. A quantitative analysis of the kinetics of labeling of specific nuclear and cytoplasmic sequences indicated that a significant fraction of the mRNA sequences transcribed from genes containing these nine CHO sequences were successfully processed into mRNA. However, two of the CHO mRNA sequences were only partially conserved during nuclear processing to yield mRNA. These studies demonstrated that events at two post-transcriptional levels, differential nuclear processing efficiency of different primary transcripts and cytoplasmic stability of different mRNA's, can be involved in the determination of the cytoplasmic concentrations of different mRNA's.

Structure, translation, and metabolism of the cytoplasmic copia ribonucleic acid of Drosophila melanogaster.

We have characterized the copia RNA in the cytoplasm of cultured Drosophila cells. Copia RNA was detected and purified by hybridization to DNA of the plasmid cDm 1142, which contains the copia sequence. A large fraction (2.2%) of the total cytoplasmic poly(A)+ RNA was found to be copia RNA. Cytoplasmic copia RNA displays all the characteristics expected for a messenger RNA. It possesses a poly(A) tract identical in length with that of total poly(A)+ cytoplasmic RNA. It is associated with polysomes and can be released from this association by treatment with EDTA. When purified copia RNA is added to an mRNA-dependent rabbit reticulocyte lysate, three polypeptides of 51000, 33000, and 21000 daltons are seen. We have not determined if these are different polypeptides or if the two smaller polypeptides are fragments of the 51000-dalton polypeptide. The half-life of copia cytoplasmic RNA was determined in pulse--chase experiments to be 9.5 h; this is 1.6 times longer than the half-life of the intermediate decay class of total poly(A)+ cytoplasmic RNA. These properties provide strong evidence that copia RNA functions in vivo as a messenger RNA.

Ribonucleic acid metabolism during planarian regeneration.

A method for the extraction of total RNA of the planarian Polycelis tenuis is described. This technique has been applied to the study of RNA synthesis in the course of regeneration. Synthesis of RNA begins 7 hrs after sectioning and proceeds in two phases. The first phase, from 7 to 21 hr is characterized by an increased rate of (3H) orotic acid incorporation into RNA up to the 18th after sectioning followed by a decrease between 18 and 21 hrs. The rate of precursor incorporation then had risen again in the second phase to the 30th hr and finally decreased slowly until completion of regeneration. Studies of the pool of nucleotide precursors, show that the observed variations of orotic acid incorporation into RNA reflect variations in RNA synthesis. Electrophoretic analysis of RNA labelled for 2 hrs at various times during regeneration shows that the product formed during the first phase of regeneration is mainly rRNA and low molecular weight RNA. The second phase of the regeneration process, from the 24th hr, is characterized by the appearance of both ribosomal and polydisperse RNAs. These heterogeneous RNA species are detected up to the 46th hr of regeneration, after which time rRNA again becomes predominent. The significance of the two phases of RNA metabolism of which this is the first observation during planarian regeneration is discussed in connection with other biochemical events which have been described during regeneration processes in planarians and other animals.

Transient cell cycle arrest of Saccharomyces cerevisiae by amino acid analog beta-2-DL-thienylalanine.

When treated with the amino acid analog beta-2-DL-thienylalanine, cells of the yeast Saccharomyces cerevisiae accumulated in the G1 portion of the cell cycle at the "start" event. This G1 arrest was accompanied by a rapid decrease in the rate of labeling of ribonucleic acid (RNA) with little effect on the rate of labeling of protein. When we examined which aspect of RNA metabolism was most affected by beta-2-DL-thienylalanine treatment, we found a dramatic decrease in the production of ribosomal precursor RNA. These results are consistent with previous findings which show a correlation between G1 arrest and reduced ribosomal precursor RNA production. The G1 arrest brought about be beta-2-DL-thienylalanine was transient; cells remain arrested in G1 only for several hours. Release from G1 arrest appeared to be accompanied either by metabolism or sequestration of the analog.

Effect of erythro-9-(2-hydroxy-3-nonyl) adenine on purine and pyrimidine metabolism in the human peripheral lymphocyte during the early phases of phytohemagglutinin-mediated blastogenesis

The effect of erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) on purine, pyrimidine and ribonucleic acid metabolism in the human peripheral lymphocyte during the early phases of blastogenesis has been studied. Experiments that determine the incorporation of radioactive free base or nucleoside into their respective nucleotides indicated EHNA-inhibited phosphoribosylpyrophosphate-dependent reactions, nucleoside kinase reactions and RNA synthesis. Studies utilizing the separating and quantitating ability of high pressure liquid chromatography demonstrated that 5–10 μM EHNA increased the nucleotide pool size of ADP without significantly changing the pool sizes of ATP, GTP or UTP. It also greatly increased the incorporation of deoxy-adenosine into dADP and dATP. Higher concentrations of EHNA (15–100 μM) reduced all the measured nucleotide pool sizes when compared to the values observed at the lower EHNA concentration. In addition, 5–10 μM EHNA significantly reduced the energy level of the cell, which was not further altered by higher concentrations of EHNA. Our studies also determined that EHNA inhibited human lymphocyte guanase and indirectly increased glycolysis and respiration.

Messenger ribonucleic acid metabolism in mammalian mitochondria: relationship between the decay of mitochondrial mRNA and their poly(A)

The mitochondrial poly(adenylic acid)-containing mRNAs in mouse ascites cells pulsed with radioactive precursors contain 35-55 nucleotide long poly(adenylic acid) sequences. These sequences are shortened with age in cells chased with cold medium. The possible relationship between the decay rates of mRNA and their poly(adenylic acid) sequences has been investigated by using mitochondrial RNA and protein synthesis inhibitors. The pattern of mRNA decay as determined by a new solid-phase-bound complementary DNA procedure indicates the presence of two classes of poly(adenylic acid) containing mRNA in mammalian mitochondria: one decaying with a t1/2 of 45 min and the other class with a t1/2 of 210 min. Inhibitors such as ethidium bromide and puromycin which accelerate the decay of mitochondrial mRNA also cause an enhanced decay of poly(adenylic acid) sequences. These results have been interpreted as evidence supporting the involvement of poly(adenylic acid) sequences in the mRNA stability.

Effect of ginseng saponins on nuclear ribonucleic acid (RNA) metabolism. II. RNA polymerase activities in rats treated with ginsenoside.

The activities of ribonucleic acid (RNA) polymerases I, II and III in a sodium deoxycholate (DOC)-treated enzyme preparation have been differentially determined using three combinations of assay conditions (metal ion ; Mg2+ or Mn2+, (NH4)2SO4 and α-amanitin). Ginsenoside-Rb1 enhanced, while -Rc repressed, the activities of RNA polymerases I and II, whereas both had no effect on that of RNA polymerase III. Rb1-treated rats showed different profiles of stimulation of RNA polymerases I and II ; the maximum increase of RNA polymerase I activity was about +70% at 2 hr, and that of RNA polymerase II activity was +40% at 3 hr after the injection of Rb1. Actinomycin D and cycloheximide both blocked the increase in RNA polymerase I activity on treatment with ginsenoside-Rb1. On the other hand, increased activity of RNA polymerase II was blocked by actinomycin D but not by cycloheximide. These results suggest transcriptional regulation in the enhancement by ginsenoside-Rb1 of RNA polymerase activities I and II, though the mechanisms may differ in detail.

Modifications of major aspects of myocardial ribonucleic acid metabolism as a response to noradrenaline. Behaviour of polyadenylate polymerase and ribonucleic acid polymerase, acetylation of histones and rate of synthesis of polyamines

Noradrenaline added to perfused rabbit heart previously perfused with labelled precursors causes, after 2.5 and 5.0 min, a general increase of specific radioactivity or RNA in subcellular fractions, but no augmentation of acetylation of F2a2 and F2a1 histone fractions and no stimulation of DNA-dependent RNA polymerase activities. Synthesis of spermidine and spermine is enhanced at 10.0 min of treatment, when there is also a fall in specific radioactivity of RNA. The cytoplasmic Mn2+-stimulated polyadenylate polymerase activity is strongly enhanced 30s to 2.5 min after injection of noradrenaline or of dibutyryl cyclic AMP. Both the cyclic nucleotide and noradrenaline have no influence in vitro on the polyadenylate polymerase reaction.

Modifications of major aspects of myocardial ribonucleic acid metabolism as a response to noradrenaline. Action of the hormone on cytoplasmic processing of ribonucleic acid after reserpine treatment.

Treatment of perfused rabbit heart with reserpine causes a decrease of incorporation of labelled precursors into RNA species of subcellular fractions and polyamines. Ornithine decarboxylase, S-adenosylmethionine decarboxylase and cytoplasmic Mn2+-stimulated polyadenylate polymerase activities are not modified. Addition of noradrenaline to reserpine-treated perfused hearts enhances, compared with the control, the incorporation of precursor into RNA in all subcellular fractions other than the nuclear one, restores incorporation of labelled putrescine into polyamines, enhances ornithine decarboxylase and S-adenosylmethionine decarboxylase activities and causes a 12-fold increase in cytoplasmic Mn2+-dependent polyadenylate polymerase activity. After treatment with noradrenaline the increase in radioactivity was found solely in AMP after hydrolysis of microsomal RNA to nucleoside monophosphates.

Metabolism of arginine-specific messenger ribonucleic acid in Escherichia coli K-12

Ribonucleic acid-deoxyribonucleic acid (RNA-DNA) hybridization was employed for the determination of the level of messenger RNA (mRNA) transcribed from seven of the nine genes of the arginine regulon of Escherichia coli K-12. The quantity of RNA complexing with each of the separated DNA strands of the argA, argF, argE, and argCBH operons carried on specialized transducing phages was measured. The derepressed:repressed ratio of mRNA formed in vivo was found to vary between about 3 and 4 when measured by hybridization to DNA isolated from specialized transducing phages carrying the argA, argE, argCBH, argF, and argI operons.

Regulation of Ribonucleic Acid Metabolism by Plant Hormones

INTRODUCTION ...... . . . ...... ..... .... .. ......... .. .. ........ . 538 HORMONAL MODIFICATION OF RNA METABOLISM . 538 Auxin 538 Receptors and mediators 538 Regulation of transcription (isolated nuclei, chromatin, and DNA) 540 Polymerases ....... ... ...... ... .... 542 Regulation of RNA metabolism in vivo ......... 543 Gibberellins .. ..... ....... ..... ......... .. .. ... 545 Receptors 545 Regulation of transcription (isolated nuclei, chromatin, and DNA) 545 Regulation of RNA metabolism in vivo 546 Cytokinins . ..... ... 549 Receptors ... ..... ... 549

Ribonucleoproteins and heterogeneous nuclear ribonucleic acid metabolism in isolated HeLa-cell nuclei.

Conference Article| June 01 1977 Ribonucleoproteins and Heterogeneous Nuclear Ribonucleic Acid Metabolism in Isolated HeLa-Cell Nuclei ROY H. BURDON; ROY H. BURDON 1Department of Biochemistry, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K. Search for other works by this author on: This Site PubMed Google Scholar ADRIAN SLATER; ADRIAN SLATER 2Department of Biochemistry, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K. Search for other works by this author on: This Site PubMed Google Scholar TOM STRACHAN; TOM STRACHAN 3Department of Biochemistry, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K. Search for other works by this author on: This Site PubMed Google Scholar JESSIE T. DOUGLAS JESSIE T. DOUGLAS 4Department of Biochemistry, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1977) 5 (3): 632–633. https://doi.org/10.1042/bst0050632 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation ROY H. BURDON, ADRIAN SLATER, TOM STRACHAN, JESSIE T. DOUGLAS; Ribonucleoproteins and Heterogeneous Nuclear Ribonucleic Acid Metabolism in Isolated HeLa-Cell Nuclei. Biochem Soc Trans 1 June 1977; 5 (3): 632–633. doi: https://doi.org/10.1042/bst0050632 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search Keywords: hnRNA, heterogeneous nuclear RNA, Hepes, 4-(2-hydroxyethyl)-2-piperazine-ethanesulphonic acid This content is only available as a PDF. © 1977 Biochemical Society1977 Article PDF first page preview Close Modal You do not currently have access to this content.

Isolation and characterization of a polynucleotide phosphorylase from Bacillus amyloliquefaciens.

Bacillus amyloliquefaciens BaM-2 produces large amounts of extracellular enzymes, and the synthesis of these proteins appears to be dependent upon abnormal ribonucleic acid metabolism. A polynucleotide phosphorylase (nucleoside diphosphate:polynucleotide nucleotidyl transferase) was identified, purified, and characterized from this strain. The purification scheme involved cell disruption, phase partitioning, differential (NH4)2SO4 solubilities, agarose gel filtration, and diethylaminoethyl-Sephadex chromatography. The purified enzyme demonstrated the reactions characteristic of polynucleotide phosphorylase: polymerization, phosphorolysis, and inorganic phosphate exchange with the beta-phosphate of a nucleotide diphosphate. The enzyme was apparently primer independent and required a divalent cation. The reactions for the synthesis of the homopolyribonucleotides, (A)n and (G)n, were optimized with respect to pH and divalent cation concentration. The enzyme is sensitive to inhibition by phosphate ion and heparin and is partially inhibited by rifamycin SV and synthetic polynucleotides.

Messenger ribonucleic acid metabolism during myogenesis.

Messenger ribonucleic acid metabolism during myogenesis.

Ribonucleic acid metabolism during the development and ripening of tomato fruits

The accumulation of RNA in the outer locule tissue of tomato fruits was measured during development and ripening. Labelling studies suggest two peaks of synthesis, the first during early development and the second just before the onset of ripening (colour change). During the second period of increased RNA labelling the amount of total RNA per fruit either remains constant or starts to decline. Synthesis of rRNA and soluble RNA occurred at all stages. Polydisperse RNA containing polyadenylic acid was isolated and shown to direct the synthesis of protein in vitro. No significant changes in the amount of polyadenylic acid, relative to total RNA were detectable during the ripening period.