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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The leader RNA transcript of vesicular stomatitis virus inhibits transcription of the adenovirus major late promoter and virus-associated genes in a soluble HeLa cell transcription system. We examined the specific nucleotide sequence involved and the potential role of leader-protein interactions in this inhibition of RNA polymerase II- and III-directed transcription. Using synthetic oligodeoxynucleotides homologous to regions of the leader RNA molecule, we extend our previous results (B.W. Grinnell and R.R. Wagner, Cell 36:533-543, 1984) that suggest a role for the AU-rich region of the leader RNA or the homologous AT region of a cloned cDNA leader in the inhibition of DNA-dependent transcription. Our results indicate that a short nucleotide sequence (AUUAUUA) or its deoxynucleotide homolog (ATTATTA) appears to be the minimal requirement for the leader RNA to inhibit transcription by both RNA polymerases, but sequences flanking both sides of this region increase the inhibitory activity. Nucleotide changes in the homologous AT-rich region drastically decrease the transcriptional inhibitory activity. Leader RNAs from wild-type virus, but not from a 5'-defective interfering particle, form a ribonuclease-resistant, protease-sensitive ribonucleoprotein complex in the soluble HeLa cell extract. Several lines of evidence suggest that the leader RNA specifically interacts with a 65,000-dalton (65K) cellular protein. In a fractionated cell extract, only those fractions containing this 65K protein could reverse the inhibition of DNA-dependent RNA synthesis by the plus-strand vesicular stomatitis virus leader RNA or by homologous DNA. In studies with synthetic oligodeoxynucleotides homologous to leader RNA sequences, only those oligonucleotides containing the inhibitory sequence were able to bind to a gradient fraction containing the 65K protein.
Mol Cell Biol 1985 Oct
PMID:Inhibition of DNA-dependent transcription by the leader RNA of vesicular stomatitis virus: role of specific nucleotide sequences and cell protein binding. 301 5

We examined the relationship between pre-mRNA splicing and the nuclear matrix by using an in vivo system that we have developed. Plasmids containing the inducible herpesvirus tk gene promoter linked to an intron-containing segment of the rabbit beta-globin gene were transfected into HeLa cells, and then the promoter was transactivated by infection with a TK- virus. Northern analysis revealed that the globin pre-mRNA and all its splicing intermediates and products are associated with the nuclear matrix prepared from such transfected cells. When the nuclear matrix was incubated with a HeLa cell in vitro splicing extract in the presence of ATP, the amount of matrix-associated precursor progressively decreased without a temporal lag in the reaction, with a corresponding increase in free intron lariat. Thus, most of the events of the splicing process (endonucleolytic cuts and branching) occur in this in vitro complementation reaction. However, ligation of exons cannot be monitored in this system because of the abundance of preexisting mature mRNA. Since the matrix is not a self-splicing entity, whereas the in vitro splicing system cannot process efficiently deproteinized matrix RNA, we conclude from our in vitro complementation results (which can be reproduced by using micrococcal nuclease-treated splicing extract) that the nuclear matrix preparation retains parts of preassembled ribonucleoprotein complexes that have the potential to function when supplemented with soluble factors (presumably other than most of the small nuclear ribonucleoproteins known to participate in splicing) present in the HeLa cell extract.
Mol Cell Biol 1987 Jan
PMID:Pre-mRNA splicing and the nuclear matrix. 303 50

The contribution of lysine and arginine residues to the formation of yeast ribonucleoprotein complex 5S RNA. protein YL3 has been investigated by determining the effects on complex formation of modification with chemical reagents specific for either lysine or arginine. Treatment of protein YL3 with acetic anhydride, maleic anhydride or phenylglyoxal is accompanied by loss of its capacity to bind to 5S RNA. This effect is accomplished by modification with phenylglyoxal of only 3 arginine residues per YL3 molecule. In contrast, a large number of protein YL3 amino groups must be modified by acetic anhydride to prevent complex formation.
Mol Cell Biochem 1987 Aug
PMID:Involvement of lysine and arginine residues in the binding of yeast ribosomal protein YL3 to 5S RNA. 311 84

Nucleolin is a multifunctional nucleolar protein involved in the synthesis, packaging and maturation of pre-rRNA in eukaryotic cells. We describe the molecular organization and complete sequence of the mouse nucleolin gene, the first higher eukaryotic gene encoding a protein that is both an RNA binding protein involved in rRNA processing and a specific nucleolar protein. The nucleolin gene extends over 9000 base-pairs and is split into 14 exons that encode the 706 amino acid residues of the protein. The promoter sequence is G + C-rich (67% G + C) with four G/C boxes, it lacks bona fide TATA and CAAT boxes and shows capping site heterogeneity. The existence of pyrimidine-rich motifs, similar to those found in the promoter of ribosomal protein genes, could be relevant to the co-regulation of genes whose products are involved in ribosome biogenesis. Nucleolin contains four RNA binding domains, each about 80 amino acid residues long, which include the 11-residue core ribonucleoprotein consensus motif. Each domain is encoded by two exons, with an intervening sequence interrupting the conserved core motif at roughly the same amino acid position. This latter result suggests that the RNA binding domains are composed of two independent subdomains, whose functions remain to be determined.
J Mol Biol 1988 Apr 20
PMID:Structure of the mouse nucleolin gene. The complete sequence reveals that each RNA binding domain is encoded by two independent exons. 313 46

The decay rates of eucaryotic elongation factor Tu (eEF-Tu) mRNA and eucaryotic initiation factor 4A (eIF-4A) mRNA in Friend erythroleukemia (FEL) cells were determined under several different growth conditions. In FEL cells which were no longer actively dividing (stationary phase), eEF-Tu mRNA was found to be rather stable, with a t1/2 of about 24 h. In rapidly growing FEL cells eEF-Tu mRNA was considerably less stable, with a t1/2 of about 9 h. In both cases a single rate of mRNA decay was observed. However, when stationary-phase cells resumed growth after treatment with fresh medium, we observed that eEF-Tu mRNA decay followed a biphasic process. The faster of the two decay rates involved approximately 50% of the eEF-Tu mRNA and had a t1/2 of about 1 h. The decay rates for eIF-4A (t1/2 = 2 h) and total poly(A)+ RNA (t1/2 = 3 h) were unaffected by changes in growth conditions. The t1/2 for polysomal eEF-Tu mRNA was found to be about 8 h when stationary FEL cells were treated with fresh medium. Previous work in this laboratory has shown (T. R. Rao and L. I. Slobin, Mol. Cell. Biol. 7:687-697, 1987) that when FEL cells are allowed to grow to stationary phase, approximately 60% of the mRNA for eEF-Tu is found in a nontranslating postpolysomal messenger ribonucleoprotein (mRNP) particle. eEF-Tu mRNP was rapidly cleared from stationary cells after treatment with fresh medium. The data presented in this report indicate that the stability of eEF-Tu mRNP is rapidly altered and the particle is targeted for degradation when stationary FEL cells resume growth.
Mol Cell Biol 1988 Mar
PMID:The stability of mRNA for eucaryotic elongation factor Tu in Friend erythroleukemia cells varies with growth rate. 316 9

The organization of select proteins within ribonucleoprotein particles containing heterogeneous nuclear and uridine-rich small nuclear RNAs (hnRNP and UsnRNP respectively) was examined by chemical cross-linking and ribonuclease digestion using diagonal two dimensional PAGE and immunoblotting detection systems. Monoclonal antibodies specific for A2, C1 and C2 hnRNP proteins, detected these proteins at gel coordinates which suggested homotypic dimers and trimers of A2 and homotypic trimers, hexamers and larger multimers of C1 and C2. Ribonuclease digestion did not alter the cross-linking properties of hnRNP C1 and C2 proteins but did result in loss of A2 homotypic dimers and trimers. Blots simultaneously reacted with hnRNP specific monoclonal antibodies and autoimmune patient serum (RNP/Sm), or monoclonal antibodies reactive with the U1 snRNP specific 63 kDa protein and/or the UsnRNP common proteins B', B and D revealed no complexes which would indicate interactions between hnRNPs and UsnRNPs. The U1 UsnRNP specific 63 kDa protein appeared not to be cross-linked to UsnRNP common B', B and D proteins. The data also suggested that UsnRNP common protein D was cross-linkable to UsnRNP common proteins D', E and G but not to B' and B. The cross-linking properties of D were unaffected by ribonuclease digestion. In contrast, ribonuclease digestion resulted in an inability to cross-link select complexes containing either B' and B, or p63. The data suggest that both hnRNPs and UsnRNPs are comprised of RNA-dependent and RNA-independent protein-protein interactions.
Mol Cell Biochem 1988 Nov
PMID:Reversible chemical cross-linking and ribonuclease digestion analysis of the organization of proteins in ribonucleoprotein particles. 323 Dec 14

Newly synthesized small nuclear RNA (snRNA) species U1 and U2 are easily identified in cytoplasmic fractions prepared by standard aqueous cell fractionation. However, because the mature stable snRNA species leak from isolated nuclei during cell fractionation, the possibility exists that these newly synthesized species also leak from the nucleus. To overcome the problems of nuclear leakage, mouse L929 cells were fractionated by cell enucleation. Enucleation extrudes the nuclei from cytochalasin-treated cells and produces cytoplasts that, by several criteria, are a bona fide cytoplasmic fraction uncontaminated by nuclear material. All six of the major snRNAs are present in the cytoplasts (c-snRNAs) shortly after synthesis. The species are identified by immunoprecipitation with specific antisera against the ribonucleoproteins and by Northern blotting and hybrid selection using cloned probes. This confirms and extends similar studies that used non-aqueous cell fractionation and manual dissection to overcome nuclear leakage. Kinetic studies demonstrate that the c-snRNAs return to the interphase nucleus after approximately 20 minutes in the cytoplasm. The U2 precursor U2' is processed to mature-sized U2 in the cytoplast fractions before returning to the nucleus. The c-snRNAs occur in ribonucleoprotein particles with similar antigenicity to the mature nuclear particles within six minutes of transcription. This suggests that in mammalian cells, important steps in the assembly of these ribonucleoproteins occur in the cytoplasm.
J Mol Biol 1988 Jan 20
PMID:Newly synthesized small nuclear RNAs appear transiently in the cytoplasm. 335 25

Oligonucleotides derived from the spacer element of the histone RNA 3' processing signal were used to characterize mouse U7 small nuclear RNA (snRNA), i.e., the snRNA component active in 3' processing of histone pre-mRNA. Under RNase H conditions, such oligonucleotides inhibited the processing reaction, indicating the formation of a DNA-RNA hybrid with a functional ribonucleoprotein component. Moreover, these oligonucleotides hybridized to a single nuclear RNA species of approximately 65 nucleotides. The sequence of this RNA was determined by primer extension experiments and was found to bear several structural similarities with sea urchin U7 snRNA. The comparison of mouse and sea urchin U7 snRNA structures yields some further insight into the mechanism of histone RNA 3' processing.
Mol Cell Biol 1988 Apr
PMID:Structural and functional characterization of mouse U7 small nuclear RNA active in 3' processing of histone pre-mRNA. 338 87

In this study an unprecedented demonstration of the detection sensitivity of electron spectroscopic imaging (ESI) is reported. This microanalytical technique is capable of forming elemental maps of a specimen with high sensitivity and resolution by forming images with electrons that have lost particular amounts of energy due to interactions with the atoms of the specimen. The 7-S ribonucleoprotein particle, composed of one molecule of 5-S RNA and one molecule of the 40K MW protein, TFIIIa, was used for this demonstration. As few as 120 phosphorus atoms of the 5-S RNA have been detected and their localization in the particle determined. The shape of the 7-S particle is ellipsoidal with a long axis of 15.0 nm and a shorter axis between 8 and 9 nm. Similarly, the 5-S RNA is also an elongated structure located asymmetrically on one side of the particle. The average signal-to-noise ratio over the particle in the net phosphorus images is 14 whereas the ratio measured for the nucleosome containing 2.4-fold more phosphorus is 30.
J Ultrastruct Mol Struct Res 1988 Apr
PMID:Phosphorus imaging of the 7-S ribonucleoprotein particle. 340 6

The 5' ends of Leishmania mRNAs contain an identical 35-nucleotide sequence termed the spliced leader (SL) or 5' mini-exon. The SL sequence is at the 5' end of an 85-nucleotide primary transcript that contains a consensus eucaryotic 5' intron-exon splice junction immediately 3' to the SL. The SL is added to protein-coding genes immediately 3' to a consensus eucaryotic 3' intron-exon splice junction. Our previous work demonstrated possible intermediates in discontinuous mRNA processing that contain the 50 nucleotides of the SL primary transcript 3' to the SL, the SL intron sequence (SLIS). These RNAs have a 5' terminus at the splice junction of the SL and the SLIS. We examined a Leishmania nuclear extract for these RNAs in ribonucleoprotein (RNP) particles. Density centrifugation analysis showed that the SL RNA is predominantly in RNP complexes at 60S, while the SLIS-containing RNAs are in complexes at 40S. We also demonstrated that the SLIS can be released from polyadenylated RNA by incubation with a HeLa cell extract containing debranching enzymatic activity. These data suggested that Leishmania enriettii mRNAs are assembled by bimolecular or trans splicing as has been recently demonstrated for Trypanosoma brucei. Furthermore, we determined the partial sequence of the Leishmania U2 equivalent RNA and demonstrated that it cosediments with the SL RNA at 60S in a nuclear extract. These RNP particles may be analogous to so-called spliceosomes that have been demonstrated in other systems.
Mol Cell Biol 1988 Jun
PMID:trans splicing in Leishmania enriettii and identification of ribonucleoprotein complexes containing the spliced leader and U2 equivalent RNAs. 340 14


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