Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A monoclonal antibody defines an antigen, p68, related to hsp70, which is located in nuclei of uninfected exponential cells. Nuclear p68 is released by DNase but not RNase treatment suggesting an association with DNA. Lytic productive infection of confluent quiescent BHK 21 cells with herpes simplex virus type-2 causes p68 to accumulate in nuclei. The effect is specific for HSV-2, and does not occur in HSV-1 infected cells. Maximum nuclear accumulation of p68 requires virus DNA synthesis although a significant accumulation occurs in the absence of such synthesis. It is suggested that the nuclear accumulation of p68 is an aspect of a cellular stress response to lytic infection with HSV-2.
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PMID:Nuclear accumulation of a heat-shock 70-like protein during herpes simplex virus replication. 282 4

We have partially purified ribonucleoproteins (RNPs) from Schizosaccharomyces pombe and Yarrowia lipolytica with properties resembling those of mammalian signal recognition particle (SRP). In both species of yeast we have identified a single major RNA species in the size range of SRP RNA (256 nucleotides in S. pombe and 270 nucleotides in Y. lipolytica) present in postribosomal salt extracts of the cytoplasm. The RNPs containing these RNAs sediment in sucrose gradients at 11 S and 10 S for S. pombe and Y. lipolytica, respectively. Analysis of genomic clones of these RNAs has revealed that (i) they are encoded by single copy genes; (ii) they share two short conserved sequences that match the A and B boxes defined for polymerase III promoters; (iii) they can be folded into secondary structures that closely match that defined by phylogenetic analysis of higher eukaryotic SRP RNAs; and (iv) they show primary sequence conservation in short regions predicted to be single stranded. Both of the yeast RNAs bind under stringent conditions to canine SRP proteins. Most importantly, RNase protection of the S. pombe RNA by the individual canine SRP proteins, p19 and p68/72, shows that the proteins recognize homologous elements of the mammalian and yeast RNA. Taken together these data suggest strongly that we have identified yeast SRP homologues.
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PMID:Small ribonucleoproteins in Schizosaccharomyces pombe and Yarrowia lipolytica homologous to signal recognition particle. 283 64

Using data derived from peptide sequencing of p68/70, a protein doublet induced during optic nerve regeneration in goldfish, we have isolated cDNAs that encode RICH (regeneration-induced CNPase homolog) from a goldfish regenerating retina cDNA library. The predicted RICH protein comprises 411 amino acids, possesses a pI of 4.48, and shows significant homology to the mammalian myelin marker enzyme 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase; EC 3.1.4.37). The mRNA encoding RICH was demonstrated, by both Northern blot analysis and RNase protection assays, to be induced as much as 8-fold in regenerating goldfish retinas at 20 days after nerve crush. Analysis of total RNA samples from various tissues showed a broad distribution of RICH mRNA, with the highest levels observed in gravid ovary. The data obtained strongly suggest that RICH is identical or very similar to p68/70. The molecular cloning of RICH provides the means for a more detailed analysis of its function in nerve regeneration. Additionally, the homology of RICH and CNPase suggests that further investigation may provide additional insight into the role of these proteins in the nervous system.
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PMID:Isolation of cDNA clones encoding RICH: a protein induced during goldfish optic nerve regeneration with homology to mammalian 2',3'-cyclic-nucleotide 3'-phosphodiesterases. 756 86

The RNA stem-loop structure of the trans-activating region TAR sequence of human immunodeficiency virus-1 mRNA is the binding site for a number of host cell proteins. A virtually identical set of proteins from HeLa nuclear extracts was found to bind to the predicted RNA hairpin element of prion protein (PrP) mRNA, as demonstrated in UV cross-linking/RNase protection and Northwestern assays. We show that the cellular TAR loop-binding protein, p68, is among those proteins which associate with PrP RNA. Competition experiments with various TAR RNA mutants revealed that binding of partially purified p68 to PrP RNA stem-loop occurs sequence-specifically. The 100-kDa 2-5A synthetase which is involved in the cellular antiviral defense was able to bind to PrP mRNA stem-loop in Northwestern blots with cytosolic proteins from HeLa cells treated with interferon. However, the PrP RNA failed to activate this enzyme in vitro, in contrast to TAR RNA.
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PMID:Interaction of 68-kDa TAR RNA-binding protein and other cellular proteins with prion protein-RNA stem-loop. 922 82

The U1 snRNP-A (U1A) protein has been known for many years as a component of the U1 snRNP. We have previously described a form of U1A present in human cells in significant amounts that is not associated with the U1 snRNP or U1 RNA but instead is part of a novel complex of non-snRNP proteins that we have termed snRNP-free U1A, or SF-A. Antibodies that specifically recognize this complex inhibit in vitro splicing and polyadenylation of pre-mRNA, suggesting that this complex may play an important functional role in these mRNA-processing activities. This finding was underscored by the determination that one of the components of this complex is the polypyrimidine-tract-binding protein-associated splicing factor, PSF. In order to further our studies on this complex and to determine the rest of the components of the SF-A complex, we prepared several stable HeLa cell lines that overexpress a tandem-affinity-purification-tagged version of U1A (TAP-tagged U1A). Nuclear extract was prepared from one of these cell lines, line 107, and affinity purification was performed along with RNase treatment. We have used mass spectrometry analysis to identify the candidate factors that associate with U1A. We have now identified and characterized PSF, p54(nrb), and p68 as novel components of the SF-A complex. We have explored the function of this complex in RNA processing, specifically cleavage and polyadenylation, by performing immunodepletions followed by reconstitution experiments, and have found that p54(nrb) is critical.
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PMID:p54nrb is a component of the snRNP-free U1A (SF-A) complex that promotes pre-mRNA cleavage during polyadenylation. 1637 96

The human Ewing Sarcoma (EWS) protein belongs to the TET family of RNA-binding proteins and consists of an N-terminal transcriptional activation domain (EAD) and a C-terminal RNA-binding domain (RBD), which is extensively methylated at arginine residues. This multifunctional protein acts in transcriptional co-activation, DNA-recombination, -pairing and -repair, in splicing, and mRNA transport. The role of arginine methylation in these processes as well as the time and place of methylation within cells is still unclear. In this study, we show that methylation of recombinant EWS protein in HEK cells occurs immediately after or even during translation. Pull-down experiments with recombinant EWS protein as bait, followed by mass spectrometric analysis identified more than 30 interacting proteins independent of whether the EWS protein was methylated or not. The EWS protein interacts via its RBD with RNase-sensitive protein complexes consisting of mainly heterogeneous nuclear ribonucleoproteins (hnRNPs) and RNA helicases. HnRNP M and U, the RNA-helicases p68 and p72, but also actin and tubulin were found to interact directly with the EWS protein. Co-precipitation experiments with recombinant proteins confirmed the interaction of the EWS protein with p68 via its RBD. Colocalization of the EWS protein and the RNA-helicases in the nucleus of HEK cells was visualized by expressing labeled EWS protein and p68 or p72. When co-expressed, the labeled proteins relocated from the nucleoplasm to nucleolar capping structures. As arginine methylation within the RBD of the EWS protein are neither needed for its subcellular localization nor for its protein-protein interaction, a role of EWS protein methylation in RNA-binding and affecting the activation/repression activity or even in the stabilization of the EWS protein seems very likely.
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PMID:Analysis of Ewing sarcoma (EWS)-binding proteins: interaction with hnRNP M, U, and RNA-helicases p68/72 within protein-RNA complexes. 1967 43

Cyclooxygenase (COX) catalyzes the first step in prostanoid biosynthesis and exists as two isoforms. COX-1 is a constitutive enzyme involved in physiological processes, whereas COX-2 is induced by a variety of stimuli. MicroRNAs (miRNAs) are noncoding RNAs that function as key posttranscriptional regulators of gene expression. Although it is known that COX-2 expression is regulated by miRNAs, there are no data regarding COX-2 involvement in miRNA regulation. Considering our previous results showing that COX-2 expression in hepatocytes protects against insulin resistance, we evaluated the role of COX-2 in the regulation of a specific set of miRNAs implicated in insulin signaling in liver cells. Our results provide evidence of the molecular basis for a novel function of COX-2 in miRNA processing. COX-2 represses miRNA 23b (miR-23b), miR-146b, and miR-183 expression in liver cells by increasing the level of DEAD-box helicase p68 (DDX5) through phosphatidylinositol 3-kinase (PI3K)/p300 signaling and by modulating the enzymatic function of the Drosha (RNase type III) complex through its physical association with DDX5. The decrease of miR-183 expression promotes protection against insulin resistance by increasing insulin receptor substrate 1 (IRS1) levels. These results indicate that the modulation of miRNA processing by COX-2 is a key event in insulin signaling in liver and has potential clinical implications for the management of various hepatic dysfunctions.
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PMID:Regulation of MicroRNA 183 by Cyclooxygenase 2 in Liver Is DEAD-Box Helicase p68 (DDX5) Dependent: Role in Insulin Signaling. 2596 60