Size of the poly(A) region in mouse globin messenger RNA

A 9S RNA fraction from mouse reticulocytes, containing the active - and -globin mRNAs, has been isolated by hybridization of the polyadenylate regions in the mRNAs to oligo(dT)-cellulose. The adenylate-rich sequence isolated by limited RNase digestion of the globin mRNAs migrates between 4S and 5S RNA standards when co-electrophoresed on 12% polyacrylamide gels. Poly(A) standards, 28 and 84 nucleotides in length, showed anomolous migration relative to the 4S and 5S RNAs. The average size of the adenylate-rich sequence, estimated by its migration relative to the poly(A) standards, is about 50 nucleotides. The polyadenylate stretch in mouse globin mRNA is therefore much shorter than those found in other mRNAs.     

Hepatic nuclease. 2. Association of polyadenylase, alkaline ribonuclease and deoxyribonuclease with rat-liver mitochondria.

Six types of nuclease activities were found to be concentrated in the large granule fraction isolated from rat liver homogenastes by differential centrifugation. Analysis by density equilibration shows that three nucleases are associated with mitochondria: an alkaline ribonulcease (pH optimum 8.8), an alkaline deoxyribonuclease (pH optimum 7.6) and an enzyme acting on polyriboadenylate (pH optimum 7.5). When the outer mitochondrial membrane is ruptured in hypotonic medium, the three mitochondrial nucleases are partially solubilized. Solubilization is however obtained by addition of KCL to the suspension medium. It is concluded that mitochondrial nucleases are localized in the intermembrane space but that an adsorption to the outer face of the inner mitochondrial membrane occurs in sucrose 0.25 M. The mitochondrial localization of alkaline ribonuclease, alkaline deoxyribonuclease and polyadenylate accounts for at least 80% of the activity of liver homogenate; nevertheless, an excess of these enzymes is present in the microsomal fraction. Although no definite conculusion can be reached for the significance of this observation, it is shown by density equilibration analysis that these nuclease are not associated either with ribosomes or with the membranes which are the major component of the microsomal fraction.     

Adenylate-Rich Sequences in Sendai Virus Transcripts from Infected Cells

Virus-specific complementary ribonucleic acid (RNA) from cells infected with Sendai virus was isolated by a procedure involving hybridization with virion RNA and isopycnic centrifugation of the RNA hybrids. The complementary RNA contained adenylate-rich sequences which sedimented at about 4S.     

Poly adenylic acid synthesis in vitro in isolated HeLa cell nuclei and whole cell homogenates,

Homogenates of HeLa cells and purified HeLa cell nuclei were found to synthesize poly(A) in vitro. The poly(A) is the normal adenylate-rich species seen in growing cells and is contained in large RNA molecules, which themselves have been synthesized at least in part in vitro. Poly(A) synthesis in purified nuclei shows a dependence on ATP concentration that is about 75–200 times higher than the concentration for total RNA synthesis.     

Ionophorous polymers. Interaction with polynucleotides and effects on RNA-directed DNA polymerase activity.

Poly(vinylbenzo-18-crown-6), a water-soluble polymer endowed with ion-binding crown moieties as pendent groups, forms insoluble complexes with polyadenylate in the presence of K+; the corresponding monomeric benzo-18-crown-6, does not form a precipitate under the same conditions. In the presence of Na+ and Mn2+ which in aqueous solution complex weakly to crown compounds, no coprecipitation of the crown polymer and polyadenylate occurs; nevertheless, the crown polymer strongly binds to immobilized polyadenylate even under these conditions. The interactions of crown polymer with the poly-nucleotide result in a loss of templating ability of the latter. Using RNA-dependent DNA polymerase of murine leukemia virus it was found that (1) enzymatic action is efficiently inhibited even in the absence of ions which coprecipitate crown polymer and template, (2) inhibition is reversed by addition of excess polynucleotide and (3) monomeric crown does not inhibit the reaction.     

Adenylate-Rich Sequences in Vesicular Stomatitis Virus Messenger Ribonucleic Acid

Vesicular stomatitis virus (VSV)-specific messenger ribonucleic acid (mRNA) species contain sequences of adenylate-rich RNA which are more heterogeneous in their migration through sodium dodecyl sulfate-polyacrylamide gels than the corresponding fractions from HeLa cell mRNA. VSV virion RNA contains no adenylaterich sequences. The possible role of such sequences in the mRNA species of a cytoplasmically replicating virus is discussed.     

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.     

Nuclear and chloroplast poly(A) polymerases from plants share a novel biochemical property

Poly(A) polymerases are centrally involved in the process of mRNA 3' end formation in eukaryotes. In animals and yeast, this enzyme works as part of a large multimeric complex to add polyadenylate tracts to the 3' ends of precursor RNAs in the nucleus. Plant nuclear enzymes remain largely uncharacterized. In this report, we describe an initial analysis of plant nuclear poly(A) polymerases (nPAPs). An enzyme purified from pea nuclear extracts possesses many features that are seen with the enzymes from yeast and mammals. However, the pea enzyme possesses the ability to polyadenylate RNAs that are associated with polynucleotide phosphorylase (PNP), a chloroplast-localized enzyme involved in RNA turnover. Similar behavior is not seen with the yeast poly(A) polymerase (PAP). A fusion protein consisting of glutathione-S-transferase and the active domain of an Arabidopsis-encoded nuclear poly(A) polymerase was also able to utilize PNP, indicating that the activity of the pea enzyme was due to an interaction between the pea nPAP and PNP, and not to other factors that might copurify with the pea enzyme. These results suggest the existence, in plant nuclei, of factors related to PNP, and an interaction between such factors and poly(A) polymerases.     

Preparation and hybridization properties of oligonucleotides containing 1-alpha-D-arabinofuranosylthymine.

A pentadecanucleotide was prepared from 1-alpha-arabinofuranosylthymine. This novel oligonucleotide was found to hybridize to oligodeoxyadenylate, although not a s strongly as pentadecathymidylate. It formed duplex hybrids with both DNA and RNA complements, and triplex structures with a duplex containing a (dT)15-(dA)15 tract within a more complex strand. The Tm of the duplex with polyadenylate was almost the same as that of (dT)15 and polyadenylate, while its Tm with (dA)15 was substantially lower than that of the natural counterpart. A selective benzoylation of the 2'-O of a 5'-blocked alpha-ara-thymine was developed to greatly simplify the preparation of suitable blocked material for use in preparation of oligonucleotides on the automated DNA synthesizer.     

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.     

Direct association of messenger RNA labeled in the presence of fluoroorotate with membranes of the endoplasmic reticulum in rat liver

Liver rough endoplasmic reticulum (RER) membranes were isolated from rats given [3H]orotic acid for 48 h (ribosomal RNA [rRNA] label) or for 3 h along with 5-fluoroorotate; this latter procedure permits the labeling of cytoplasmic messenger RNAs (mRNAs) in the absence of rRNA labeling. More than 50% of the labeled mRNA remained attached to membranes of the RER after complete removal of ribosomes with a buffer of high ionic strength in the presence of puromycin. Under similar conditions, membranes retained 40% of their polyadenylate as determined by a [3H]-polyuridylate hybridization assay. Treatment of mRNA-labeled endoplasmic reticulum membranes with pancreatic RNase indicates that the polyadenylate and possibly nonpolyadenylate-pyrimidine portions of the messenger are involved in the binding of mRNA to the membranes. The implication of these results in furthering our understanding of the mechanisms of the translational regulation of genetic expression is discussed.     

Insertion/deletion polymorphism within a polyadenylate stretch at the human atrial natriuretic peptides (hANP) gene locus

A novel 8-bp bi-allelic insertion/deletion polymorphism is described within a polyadenylate stretch in the second intron of the human atrial natriuretic peptide gene locus. This new marker is located in the candidate gene for familial susceptibility to hypertension.     

Nucleotide sequence of the gene encoding respiratory syncytial virus matrix protein.

The amino acid sequence of the matrix protein of the human respiratory syncytial virus (RS virus) was deduced from the sequence of a cDNA insert in a recombinant plasmid harboring an almost full-length copy of this gene. It specifically hybridized to a single 1,050-base mRNA from infected cells. The recombinant containing 944 base pairs of RS viral matrix protein gene sequence lacked five nucleotides corresponding to the 5' end of the mRNA. The nucleotide sequence of the 5' end of the mRNA was determined by the dideoxy sequencing method and found to be 5' NGGGC, wherein the C residue is one nucleotide upstream of the cloned viral sequence. The initiator ATG codon for the matrix protein is embedded in an AATATGG sequence similar to the canonical PXXATGG sequence present around functional eucaryotic translation initiation codons. There is no conserved sequence upstream of the polyadenylate tail, unlike vesicular stomatitis virus and Sendai virus, in which four nucleotides upstream of the polyadenylate tail are conserved in all genes. There is no equivalent of the eucaryotic polyadenylation signal AAUAAA upstream of the polyadenylate tail. The matrix protein of 28,717 daltons has 256 amino acids. It is relatively basic and moderately hydrophobic. There are two clusters of hydrophobic amino acid residues in the C-terminal third of the protein that could potentially interact with the membrane components of the infected cell. The matrix protein has no homology with the matrix proteins of other negative-strand RNA viruses, implying that RS virus has undergone extensive evolutionary divergence. A second open reading frame potentially encoding a protein of 75 amino acids and partially overlapping the C terminus of the matrix protein was also identified.