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Autexier C, Triki I. Tetrahymena telomerase ribonucleoprotein RNA-protein interactions. Nucleic Acids Res 1999; 27:2227-34. [PMID: 10219097 PMCID: PMC148444 DOI: 10.1093/nar/27.10.2227] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Telomerase is an enzyme that is essential for the replication and maintenance of chromosomal termini. It is a ribonucleoprotein consisting of a catalytic subunit, one or more associated proteins, and an integral RNA subunit that serves as a template for the synthesisof telomeric repeats. We identified a Tetrahymena telomerase RNA-protein complex by an electrophoretic mobility shift assay, using telomerase partially purified from whole cell extracts and radiolabeled, in vitro transcribed wild-type Tetrahymena telomerase RNA. Complex formation was specific as unlabeled Tetra-hymena telomerase RNA, but not Escherichia coli ribo-somal RNAs, competitively inhibited complex formation. Binding required concentrations of MgCl2of at least 10 mM and occurred over a wide range of potassium glutamate concentrations (20-220 mM). The RNA-protein complex was optimally reconstituted with a 30 degrees C preincubation for </=5 min, prior to electrophoresis. Certain Tetrahymena telomerase RNAs containing deletions of structures and sequences previously predicted to be involved in protein binding were unable to competitively and specifically inhibit complex formation, suggesting a role in protein binding for the deleted residues or structures.
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Affiliation(s)
- C Autexier
- Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research,The Sir Mortimer B. Davis-Jewish General Hospital, Montréal, Quebec H3T 1E2, Canada
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Abstract
Telomerase is a ribonucleoprotein that catalyzes telomere elongation in vitro and in vivo. The 159-nucleotide RNA component of Tetrahymena telomerase contains the sequence 5'-CAACCCCAA-3' ("template region"), which serves as a template for the addition of the sequence d(TTGGGG)n to Tetrahymena telomeres. To dissect the Tetrahymena telomerase enzyme mechanism, we developed a functional in vitro reconstitution assay. After removal of the essential telomerase RNA by micrococcal nuclease digestion of partially purified telomerase, the addition of in vitro-transcribed telomerase RNA reconstituted telomerase activity. The reconstituted activity was processive and showed the same primer specificities as native telomerase. Mutants in the RNA template region were tested in reconstitution assays to determine the role of the residues in this region in primer recognition and elongation. Two template mutants, encoding the sequences 5'-UAACCCCAA-3' and 5'-UAACCCUAA-3', specified the incorporation of dATP into the sequence d(TTAGGG). Telomerase reconstituted with a template mutant encoding the sequence 5'-CAACCCUAA-3' did not specify dATP incorporation and elongation by this mutant was not terminated by the addition of ddATP. In addition, a template mutant encoding the sequence 5'-CGGCCCCAA-3' specified the incorporation of ddCTP but not ddTTP while a mutant encoding the sequence 5'-CAACCCCGG-3' specified the incorporation of ddTTP but not ddCTP. These data suggest that only the most 5' six residues of the template region dictate the addition of telomeric repeats.
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Affiliation(s)
- C Autexier
- Cold Spring Harbor Laboratory, New York 11724
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Affiliation(s)
- M A Nathanson
- Department of Anatomy, New Jersey Medical School, Newark 07103
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Lagrutta AA, McCarthy JG, Scherczinger CA, Heywood SM. Identification and developmental expression of a novel embryonic myosin heavy-chain gene in chicken. DNA (MARY ANN LIEBERT, INC.) 1989; 8:39-50. [PMID: 2707122 DOI: 10.1089/dna.1.1989.8.39] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The developmental expression of an embryonic chicken myosin heavy-chain (MHC) gene homologous to the genomic clone pCM4.1 was examined by S1 analysis. Transcripts homologous to pCM4.1 are first detected at day 12 in ovo, and are maximally expressed between days 15-17 in ovo. No pCM4.1 transcripts are detected at earlier stages of embryogenesis or at high levels in posthatch stages. This unique pattern of expression has led to the proposal that pCM4.1 represents a previously uncharacterized MHC gene, which is confined in its expression to late embryogenesis. Genomic hybridization data, in addition to a comparison between the DNA and amino acid sequences of pCM4.1 and other characterized chicken MHC 3' end clones, provide further evidence for this proposal. We also present observations made during the sequence analysis of pCM4.1 that may be relevant to our understanding of the 3'-end processing of homologous primary transcripts, and of the mechanism controlling developmental MHC isoform transitions.
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Affiliation(s)
- A A Lagrutta
- Department of Molecular and Cell Biology, University of Connecticut, Storrs 06268
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Boak AM, Kovacs SA, Agris PF, Chakraborty D, Sarkar S. Small nuclear ribonucleoprotein antigens are absent from 10S translation inhibitory ribonucleoprotein but present in cytoplasmic messenger ribonucleoprotein and polysomes. Arch Biochem Biophys 1986; 248:89-100. [PMID: 2425740 DOI: 10.1016/0003-9861(86)90404-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A cytoplasmic 10S ribonucleoprotein particle (iRNP), which is isolated from chick embryonic muscle, is a potent inhibitor of mRNA translation in vitro and contains a 4S translation inhibitory RNA species (iRNA). The iRNP particle shows similarity in size to the small nuclear ribonucleoprotein (snRNP) particles. Certain autoimmune disease patients contain antibodies directed against snRNP antigenic determinants. The possibility that iRNP may be related to the small nuclear particles was tested by immunoreactivity with monospecific autoimmune antibodies to six antigenic determinants (Sm, RNP, PM-1, SS-A (Ro), SS-B (La), and Scl-70). By Ouchterlony immunodiffusion assays, the cytoplasmic 10S iRNP did not show any immunoreactivity. Also, a more sensitive hemagglutination inhibition assay for detecting Sm and RNP antigens failed to show reactivity with the 10S iRNP. Thus, the 10S iRNP particles are distinct from the similarly sized snRNP. However, free and polysomal messenger ribonucleoprotein (mRNP) particles and polysomes also isolated from chick embryonic muscle and analyzed by Ouchterlony immunodiffusion and hemagglutination inhibition for the presence of the antigenic determinants showed reactivity to Sm and RNP autoantibodies, but were not antigenic for the other four antibodies. Some of the Sm antigenic peptides of mRNP particles and polysomes were identical to those purified from calf thymus nuclear extract, as judged by Western blot analysis. The association of Sm with free and polysomal mRNP and polysomes suggests that Sm may be involved in some cytoplasmic aspects of mRNA metabolism, in addition to a nuclear function in mRNA processing.
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Nathanson MA, Bush EW, Vanderburg C. Transcriptional-translational regulation of muscle-specific protein synthesis and its relationship to chondrogenic stimuli. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(17)36117-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Periasamy M, Wydro RM, Strehler-Page MA, Strehler EE, Nadal-Ginard B. Characterization of cDNA and genomic sequences corresponding to an embryonic myosin heavy chain. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)36337-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Firgaira FA, Hendrick JP, Kalousek F, Kraus JP, Rosenberg LE. RNA required for import of precursor proteins into mitochondria. Science 1984; 226:1319-22. [PMID: 6209799 DOI: 10.1126/science.6209799] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A cytoplasmic RNA moiety is necessary for posttranslational uptake of nuclear-encoded mammalian proteins destined for the mitochondrial matrix. Post-translational addition of ribonuclease to a reticulocyte lysate-programmed cell-free translation mixture inhibited subsequent import of six different mitochondrial matrix enzyme precursors into rat liver mitochondria. The required RNA is highly protected, as indicated by the high concentrations of ribonuclease necessary to produce this inhibition. The dependence of the inhibitory effect on temperature, duration of exposure to ribonuclease, and availability of divalent cations is characteristic of the nuclease susceptibility of ribonucleoproteins. The ribonuclease-sensitive component was found in a 400-kilodalton fraction which contains the mitochondrial protein precursors.
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DASGUPTA SHASHIPRABHA, PLUSKAL MALCOLMG, SARKAR SATYAPRIYA. Mode of Inhibition of mRNA Translation by a Novel Cytoplasmic 4 S RNA Species of Chick Embryonic Muscle. Ann N Y Acad Sci 1984. [DOI: 10.1111/j.1749-6632.1984.tb13751.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Dasgupta S, Pluskal MG, Sarkar S. The cytoplasmic 4S translation inhibitory RNA species of chick embryonic muscle: fractionation of biologically active subspecies by high performance liquid chromatography. PREPARATIVE BIOCHEMISTRY 1984; 14:331-47. [PMID: 6083558 DOI: 10.1080/10826068408070639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A 4S RNA species (iRNA) isolated from chick embryonic muscle which is a potent inhibitor of mRNA translation in vitro shows heterogeneity in the 70-100 nucleotide size range (Sarkar, S., Mukherjee, A.K., and Guha, C. (1981) J. Biol. Chem., 256, 5077-5086). The iRNA was fractionated by HPLC on different size exclusion columns using a variety of elution conditions. Chromatography of iRNA on a TSK 4000 SW column and elution with a low ionic strength buffer gave three components, one of which contained a pure subspecies of about 90-100 nucleotides size, as shown by a single band on PAGE analysis in 99% formamide. The biological activity of this purified subspecies showed that this is a more potent inhibitor of globin mRNA translation than unfractionated iRNA (Sarkar, S., Mukherjee, A.K., and Guha, C., (1981) J. Biol. Chem. 256, 5077-5086). Partial resolution of three additional low molecular weight iRNA subspecies in the 70-80 nucleotide size range in biologically active form was obtained on chromatography of unfractionated iRNA on TSK 4000 SW column in the presence of 0.5 M NaCl or on TSK 3000 SW column in the presence of low salt. The fractionation of iRNA by HPLC appears to be primarily based on size. These results strongly suggest that HPLC may also be useful for the fractionation of a variety of low molecular weight eukaryotic nuclear and cytoplasmic RNAs with retention of biological activity.
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Eller MS, Cullinan RE, McGuire PM. Isolation and characterization of a translation inhibitor from human term placenta. Arch Biochem Biophys 1984; 232:526-37. [PMID: 6205628 DOI: 10.1016/0003-9861(84)90570-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
An inhibitor of protein synthesis has been isolated from free cytoplasmic ribonucleoprotein particles of human term placenta. The inhibitor is resistant to phenol, DNase, proteinase K, and heating at 100 degrees C, but is sensitive to alkaline hydrolysis. These data suggest that the inhibitor is RNA. Experiments provide evidence that this preparation contains no RNase contaminant and does not induce an RNase in this assay system. Three lines of evidence suggest that the inhibitor acts at the initiation of protein synthesis in the wheat germ translation system. First, a lag occurs before cessation of translation when the inhibitor is added to translating polyribosomes. This lag is identical to that seen upon the addition of aurintricarboxylic acid, a known inhibitor of initiation. Second, sucrose gradient analyses demonstrate that, when the inhibitor is present at the start of translation, 40 S complexes form, but neither 80 S complexes nor polyribosomes are seen. Third, gradient analyses show that, when the inhibitor is added to translating polyribosomes, 40 S complexes accumulate with a progressive loss of polyribosomes. Finally, the extent of inhibition depends upon the amount of wheat germ extract added to the reaction mixture and not the amount of mRNA present. This suggests an interaction between the inhibitor and a component of the wheat germ extract.
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Sarkar S. Translational control involving a novel cytoplasmic RNA and ribonucleoprotein. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1984; 31:267-93. [PMID: 6085172 DOI: 10.1016/s0079-6603(08)60380-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Winkler MM, Lashbrook C, Hershey JW, Mukherjee AK, Sarkar S. The cytoplasmic 4 S translation inhibitory RNA species of chick embryonic muscle. Effect on mRNA binding to 43 S initiation complex. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)43784-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Abstract
Signal recognition particle (SRP) is a ribonucleoprotein consisting of six distinct polypeptides and one molecule of small cytoplasmic 7SL-RNA. The particle was previously shown to function in protein translocation across, and protein integration into, the endoplasmic reticulum membrane. A rapid procedure was developed to disassemble SRP into native protein and RNA components. The method utilizes unfolding of SRP with EDTA and dissociation on polycationic matrixes. SRP proteins prepared this way sediment below 7S and are inactive in activity assays. When recombined with 7SL-RNA in the presence of magnesium, the proteins are shown to reassociate stoichiometrically with 7SL-RNA to form fully active 11S SRP.
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Walter P, Blobel G. Signal recognition particle contains a 7S RNA essential for protein translocation across the endoplasmic reticulum. Nature 1982; 299:691-8. [PMID: 6181418 DOI: 10.1038/299691a0] [Citation(s) in RCA: 551] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In addition to its previously characterized, six different polypeptide components, signal recognition protein--which functions in protein translocation across and integration into the endoplasmic reticulum membrane--contains a 7S RNA molecule. The RNA is closely identified with the small cytoplasmic 7SL RNA and is required for both structural and functional properties of signal recognition protein--which we therefore rename signal recognition particle.
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Kühn B, Villringer A, Falk H, Heinrich PC. Inhibition of cell-free protein synthesis by low-molecular-weight RNAs from free cytoplasmic ribonucleoprotein particles. EUROPEAN JOURNAL OF BIOCHEMISTRY 1982; 126:181-8. [PMID: 6181991 DOI: 10.1111/j.1432-1033.1982.tb06764.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Free cytoplasmic messenger ribonucleoprotein (mRNP) particles from rat liver were treated with EDTA and separated into two populations of RNP particles with sedimentation maxima of 20 S and 35 S respectively. The 20-S and 35-S RNP particles, treated with 0.5 M KCl, have protein-to-RNA ratios of 0.31:1 and 5.7:1 respectively. Whereas 20-S and 35-S RNP particles exhibit a similar protein complement of seven major polypeptides, the low-molecular-weight RNA components of the two particle populations are different. A characteristic set of distinct low-molecular-weight RNAs is found for 20-S and 35-S RNP particles. When the individual low-molecular-weight RNAs of 20-S and 35-S RNP particles isolated from preparative polyacrylamide gels were assayed for their capability to inhibit protein synthesis in vitro, several potent translational inhibitory RNAs were detected. In particular, the low-molecular-weight RNAs of 147, 203 and 263 nucleotides in length associated with the 35-S RNP particles turned out to be strong inhibitors of protein synthesis.
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