Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently identified a nuclear matrix protein, named NMP125 for its molecular weight (M(r) 125 kDa). On the basis of immunofluorescence analysis with monoclonal anti-NMP125 antibodies of differentially extracted cells in situ, including detergents, DNase I, RNase A, and high/low ionic strength conditions, it is concluded that NMP125 is a component of a chromatin- and histone-depleted nuclear substructure, operationally defined as nuclear matrix in interphase cells. The protein revealed evolutionary conservation in man, rat, chicken, and Xenopus, at least at the level of immunological crossreactivity. The subcellular distribution of NMP125 is cell-cycle-dependent; in interphase cells NMP125 is confined to a nuclear substructure with a granular aspect, whereas after nuclear envelope breakdown, it is freed into the cytoplasm. However, most of the protein remains attached to a cytoskeletal ligand that we have identified as the intermediate-type filament vimentin. In late mitotic stages the protein forms punctuate aggregates of relatively large size, which get passively closer to the newly formed telophase nuclei together with the reorganized vimentin around the nuclei in late telophase. From the morphological point of view, although static in nature, a dynamic cell-cycle-dependent distribution of NMP125 is found, revealing dissociation and spreading throughout the cytoplasm in metaphase, binding to vimentin filaments, cytoplasmic aggregation, and transport to nuclei in telophase. The transient affinity of the nuclear protein NMP125 to vimentin filaments during mitosis together with a passive cytoplasmic dislocation of the vimentin/NMP125 conjugate toward the telophase nuclei could represent a novel and dynamic function of cytoplasmic intermediate filaments, implicating a transient repository and passive shift of nuclear proteins during mitosis.
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PMID:Transient storage of a nuclear matrix protein along intermediate-type filaments during mitosis: a novel function of cytoplasmic intermediate filaments. 148 3

Previous studies have documented nuclear insulin accumulation in a variety of cell types. The present investigation extends these observations by demonstrating that insulin associates with the matrix fraction of H35 rat hepatoma cell nuclei. Nuclei were isolated from [125I]insulin-loaded cells and extracted with DNase I, RNase A and high salt. The resulting matrix fraction was found to contain greater than 75% of the radiolabel initially present. Ultrastructural studies to confirm these findings were carried out using an agarose-encapsulated nuclear matrix preparation. Electron microscopic immunocytochemistry specifically detected insulin in matrices prepared from insulin-treated cells. No reaction was observed in matrices obtained from non-insulin-treated (control) cells. Further biochemical analysis revealed that matrix-associated insulin could be solubilized with 1% sodium dodecyl sulfate (SDS) or in the presence of high urea concentrations. Gel filtration analysis of urea-solubilized matrix material revealed the presence of apparently intact [125I]insulin and a higher molecular weight peak. It is hypothesized that the latter may represent a tightly associated complex of insulin with some matrix protein(s).
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PMID:Intranuclear localization of insulin in rat hepatoma cells: insulin/matrix association. 269 59

To detect nuclear proteins that might be involved in induction of cellular mitogenesis, we examined the effect of various mitogens on early changes in synthesis of nuclear proteins in murine B lymphocytes. Using two-dimensional gel electrophoresis, we found that activation of B cells by mitogens (anti-immunoglobulin antibody, lipopolysaccharide, phorbol 12-myristate 13-acetate (PMA)/A23187) was associated with a rapid and prominent (5-20-fold) increase in the synthesis of a 40-kDa/pI 5.0 nuclear protein, here termed numatrin. Numatrin was found to be absent from the cytosol (soluble fraction) of resting as well as activated B cells and was markedly resistant to DNase/RNase digestion and 2 N NaCl extraction, indicating that this protein is tightly bound to the nuclear matrix. Kinetic studies showed that the increase in synthesis of numatrin was detected 60-120 min following mitogen activation, reached a peak at 16 h, and declined to almost control level by 48 h, correlating with the peak of cellular DNA synthesis. The increase in synthesis of numatrin in normal B cells was found to be associated exclusively with cellular commitment for mitogenesis because activation of B cells by stimuli such as B cell stimulating factor 1, PMA alone, and calcium ionophore A23187, which do not stimulate an increase in DNA synthesis, also failed to induce an increase in the synthesis of numatrin. Inhibition of anti-Ig-induced proliferation (by PMA pretreatment) was associated with a 63% inhibition in the synthesis of numatrin. Addition of 8-mercaptoguanosine to these PMA-treated cells was associated with restoration of the increase in synthesis of numatrin, concomitant with induction of proliferation. Elevated synthesis of numatrin was also detected in the malignant B lymphoma cells: Raji, BAL-17, and WEHI-231. Taken collectively, these results suggest that numatrin, a tightly bound nuclear matrix protein, is a growth-regulated protein which might have an important role in regulation of cellular mitogenesis in normal and malignant B lymphocytes.
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PMID:"Numatrin," a nuclear matrix protein associated with induction of proliferation in B lymphocytes. 330 55

We report the characterization of a genomic clone containing portions of two tandemly arranged genes that encode a spicule matrix protein, SM30, of the sea urchin Strongylocentrotus purpuratus. The isolated 18.4-kilo-base genomic clone contains the complete genomic sequence of one SM30 gene, designated SM30-alpha, and a portion of another SM30 gene, designated SM30-beta. Southern blot analysis shows that SM30 protein is encoded by a small gene family of two to four members. RNase protection assays indicate that the SM30-alpha gene is expressed at the time of spicule formation in the sea urchin embryo. In addition, mapping of SM30-alpha shows that a large single intron interrupts the coding sequence. Comparison of the nucleic acid and amino acid sequences of the SM30-alpha genomic sequence and the previously isolated SM30 cDNA reveals them to be very similar, but not identical. We also demonstrate that 2.6 kilobases of upstream sequence of SM30-alpha are sufficient to direct primary mesenchyme cell-specific expression of a reporter gene construct.
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PMID:Genomic organization of a gene encoding the spicule matrix protein SM30 in the sea urchin Strongylocentrotus purpuratus. 805 Nov 58

Bovine respiratory syncytial virus (BRSV) is a very important pathogen of cattle and perhaps other ruminants. It is a major contributor to the incidence of respiratory tract disease in nursing beef and feedlot and dairy calves. The genome of respiratory syncytial viruses encodes 10 proteins translated from 10 unique mRNAs. The major glycoprotein (G), fusion protein (F), 1A protein and the 22K protein are components of the viral envelope. The nucleocapsid contains the nucleocapsid protein (N), the phosphoprotein (P), and the large protein (L). The matrix protein (M) forms a structural layer between the envelope and the nucleocapsid. Antibodies to all the structural proteins develop in convalescent calves. However, evidence suggests that immunity develops primarily as a result of the antigenic stimulus by the major glycoprotein G and the fusion glycoprotein F. It is known also that activated cytotoxic T cells interact with N and F protein antigens and helper T cells interact with N, F, and 1A protein antigens. With the exception of the major glycoprotein, the respective proteins of various respiratory syncytial viruses share major antigenic domains. Based on antigenic differences of the major glycoprotein, at least 3 subgroups of RSV are recognized; human A, human B, and bovine RSV. Indirect evidence suggests that a second subgroup of BRSV exists. However, we have identified only one BRSV subgroup based on our work with RNase mismatch cleavage analysis of the G protein gene from a limited number of strains. Furthermore, our data indicated that a caprine RSV isolate is closely related to the bovine strains, but an ovine isolate is not. The latter may constitute yet another subgroup of RSV. These data affect decisions on optimization of immunoprophylaxis since evidence suggests that protection against a homologous RSV subgroup virus is superior to that against a heterologous strain in immune subjects.
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PMID:Antigenic diversity of respiratory syncytial viruses and its implication for immunoprophylaxis in ruminants. 811 89

We detected elastin mRNA in cultured normal human keratinocytes by RNase protection assay. The content of elastin mRNA was estimated at approximately one-twentieth of that of cultured skin fibroblasts. Tropoelastin polypeptide with a molecular weight of 68 kDa was detected in the preparation of culture medium of normal human keratinocytes by western blot assays using anti-tropoelastin antibody. Immunohistochemical studies also demonstrated positive staining in cultured normal human keratinocytes as well as in skin fibroblasts. The expression of elastin by normal human keratinocytes was found to reach a maximum level at the quiescent phase of keratinocyte growth. When normal human keratinocytes were cultured on tropoelastin-coated dishes, their growth potential was greatly suppressed compared with other matrix protein-coated dishes. These results suggest that cultured normal human keratinocytes can actively synthesize elastin and that keratinocyte elastin may act as a growth-regulator for keratinocytes.
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PMID:Cultured human keratinocytes express tropoelastin. 934 92

Human immunodeficiency virus type 1 (HIV-1) gag-encoded proteins play key functions at almost all stages of the viral life cycle. Since these functions may require association with cellular factors, the HIV-1 matrix protein (MA) was used as bait in a yeast two-hybrid screen to identify MA-interacting proteins. MA was found to interact with elongation factor 1-alpha (EF1alpha), an essential component of the translation machinery that delivers aminoacyl-tRNA to ribosomes. EF1alpha was then shown to bind the entire HIV-1 Gag polyprotein. This interaction is mediated not only by MA, but also by the nucleocapsid domain, which provides a second, independent EF1alpha-binding site on the Gag polyprotein. EF1alpha is incorporated within HIV-1 virion membranes, where it is cleaved by the viral protease and protected from digestion by exogenously added subtilisin. The specificity of the interaction is demonstrated by the fact that EF1alpha does not bind to nonlentiviral MAs and does not associate with Moloney murine leukemia virus virions. The Gag-EF1alpha interaction appears to be mediated by RNA, in that basic residues in MA and NC are required for binding to EF1alpha, RNase disrupts the interaction, and a Gag mutant with undetectable EF1alpha-binding activity is impaired in its ability to associate with tRNA in cells. Finally, the interaction between MA and EF1alpha impairs translation in vitro, a result consistent with a previously proposed model in which inhibition of translation by the accumulation of Gag serves to release viral RNA from polysomes, permitting the RNA to be packaged into nascent virions.
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PMID:Translation elongation factor 1-alpha interacts specifically with the human immunodeficiency virus type 1 Gag polyprotein. 1036 86

To characterize the sites and nature of binding of influenza A virus matrix protein (M1) to ribonucleoprotein (RNP), M1 of A/WSN/33 was altered by deletion or site-directed mutagenesis, expressed in vitro, and allowed to attach to RNP under a variety of conditions. Approximately 70% of the wild-type (Wt) M1 bound to RNP at pH 7.0, but less than 5% of M1 associated with RNP at pH 5.0. Increasing the concentration of NaCl reduced M1 binding, but even at a high salt concentration (0.6 M NaCl), approximately 20% of the input M1 was capable of binding to RNP. Mutations altering potential M1 RNA-binding regions (basic amino acids 101RKLKR105 and the zinc finger motif at amino acids 148 to 162) had varied effect: mutations of amino acids 101 to 105 reduced RNP binding compared to the Wt M1, but mutations of zinc finger motif did not. Treatment of RNP with RNase reduced M1 binding by approximately half, but even M1 mutants lacking RNA-binding regions had residual binding to RNase-treated RNP provided that the N-terminal 76 amino acids of M1 (containing two hydrophobic domains) were intact. Addition of detergent to the reaction mixture further reduced binding related to the N-terminal 76 amino acids and showed the greatest effect for mutations affecting the RNA-binding regions of basic amino acids. The data suggest that M1 interacts with both the RNA and protein components of RNP in assembly and disassembly of influenza A viruses.
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PMID:Association of influenza virus matrix protein with ribonucleoproteins. 1043 36

Zn-alpha(2)-glycoprotein (Znalpha(2)gp) is a soluble protein widely distributed in body fluids and glandular epithelia. We have found it to be expressed in stratified epithelia as well. Znalpha(2)gp is clinically correlated with differentiation in various epithelial tumors, including oral and epidermal tumors. We have cloned epidermal Znalpha(2)gp and report the preparation of the recombinant protein in a Baculovirus expression system. Like the native molecule, recombinant Znalpha(2)gp has RNase activity. Znalpha(2)gp functions as a matrix protein for the Tu-138 oral squamous cell carcinoma cell line. Cell attachment to Znalpha(2)gp is comparable to that for fibronectin and is inhibited by the synthetic RGD peptides RGD, RGDV, and RGDS. Attachment is also inhibited by the antibody to integrin alpha(5)beta(1) (the fibronectin receptor), but not by antibodies to integrins alpha(v)beta(3), alpha(3)beta(1), and alpha(2)beta(1). We find that the proliferation of Tu-138 cells is inhibited on a Znalpha(2)gp matrix, as compared with other matrix proteins (fibronectin, vitronectin, laminin, and collagens I and IV) on which growth resembles that on the BSA control. We believe that the role of Znalpha(2)gp in differentiation and its RNase activity are two likely suspects as agents of the inhibition of proliferation.
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PMID:Characterization of zinc-alpha(2)-glycoprotein as a cell adhesion molecule that inhibits the proliferation of an oral tumor cell line. 1046 14

Vascular smooth muscle cells produce and respond to interleukin-1, a cytokine which modifies inflammation-associated vascular activities including the synthesis of extracellular matrix proteins. We have established vascular smooth muscle cells culture conditions in which heparin, in the presence of endothelial cell growth supplement, promotes cell proliferation and inhibits interleukin-1 and matrix protein expression. To test whether interleukin-1 mediates growth and matrix modulation by heparin/endothelial cell growth supplement, vascular smooth muscle cells were transfected with an Epstein-Barr virus-derived expression vector designed to express interleukin-1 antisense transcripts. RNase protection and ELISA assays demonstrated a complete block of interleukin-1 transcription and protein synthesis. Northern blot analysis also showed that interleukin-1 antisense decreased the expression of matrix genes such as type I collagen, fibronectin, and decorin similar to downregulation after heparin/endothelial cell growth supplement treatment. In contrast, the expression of versican was not affected, indicating a selective suppression of matrix proteins. In addition, interleukin-1 antisense significantly prolonged the life span of vascular smooth muscle cells in culture. Our data suggest that heparin/endothelial cell growth supplement induces matrix remodeling and controls growth and senescence of vascular smooth muscle cells through down-regulation of interleukin-1.
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PMID:Heparin/endothelial cell growth supplement regulates matrix gene expression and prolongs life span of vascular smooth muscle cells through modulation of interleukin-1. 1061 76


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