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)

Components of the extracellular matrix take part in tissue rebuilding as well as activating surface-bound growth factors. In the present study, expression and selected activities of urokinase-type plasminogen activator (uPA), matrix metalloproteinases (MMPs), their inhibitors (plasminogen activator inhibitor 1 (PAI-1) and tissue inhibitors of metalloproteinases (TIMPs)) were examined in bovine oviducts by RT--PCR, ribonuclease protection assay and activity assays. A high content of mRNA encoding for uPA was detected before ovulation with a three-fold decrease after ovulation. In contrast, PAI-1 expression appeared to be stable during the oestrous cycle. Oviductal flushings produced caseinolytic zones in zymograms containing plasminogen at approximately 50 kDa and 28 kDa. An activity assay for uPA showed highest net activity during the early to mid-luteal phase. Increased TIMP-1 and MMP-2 mRNA concentrations were found around the time of ovulation compared with the luteal phase. In contrast, MMP-1 mRNA transcripts were enriched during the early to mid-luteal phase. Gelatin zymograms detected a 70--72 kDa protease activity showing an oestrous cycle-dependent activity with highest activity before ovulation. Reverse zymography detecting TIMPs revealed proteins between 21 kDa and 24 kDa. Only for the smallest (21 kDa) protein were amounts increased around the time of ovulation compared with the luteal phase. The observation that several extracellular matrix components were regulated distinctly in bovine oviducts indicates that local interactions between these components, growth factors, gametes and the embryo are possible and may influence fertilization and early embryonic development.
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PMID:Differential expression of extracellular matrix components in the bovine oviduct during the oestrous cycle. 1142 36

Expression of aquaporin-8 mRNA has previously been shown in hepatocytes, pancreatic acinar cells, colon epithelial cells and seminiferous tubules of the testis in the rat by in situ hybridization technique. However, immunolocalization of this water channel has not yet been demonstrated. In the present study, the localization of immunoreactive aquaporin-8 and expression of the mRNA were examined in rat organs (cerebrum, cerebellum, eye, salivary gland, heart, lung, liver, pancreas, esophagus, stomach, jejunum, ileum, colon, testis, ovary, kidney, spleen and lymphnode) by immunohistochemistry using an antibody against aquaporin-8 and ribonuclease protection assay. Aquaporin-8 was distinctly immunolocalized on the apical membranes of pancreatic acinar cells and mucosal epithelium of the colon and jejunum. In the liver, the bile canalicular membrane of hepatocytes was immunostained. In the testis, immunoreactive aquaporin-8 was demonstrated on the luminal side of the seminiferous tubules. At high magnification, the peroxidase reaction products appeared on the ramified cytoplasmic membrane of Sertoli cells surrounding the residual bodies or spermatogenic cells. Specificity of the antibody was verified by Western blot analysis showing a minor approximately 28 kDa band (deduced deglycosylated form of aquaporin-8) and a major approximately 30 kDa band (glycosylated form) in these organs. The intensity of aquaporin-8 immunoreactivity was approximately comparable to that of aquaporin-8 mRNA expression in the liver, pancreas, colon, jejunum and testis. The aquaporin-8 mRNA expression in the hepatocytes was presumed to be closely associated with the structure of bile canaliculi since the message was detected in hepatocytes immediately after isolation from the liver but not in cells following cultivation for three days. The localization of immunoreactive aquaporin-8 indicated functions for this water channel in the secretion of bile and pancreatic juice, and the secretion or absorption of water in the colon and jejunum, and the maturation or liberation of spermatogenic cells in the testis.
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PMID:Immunolocalization of aquaporin-8 in rat digestive organs and testis. 1143 86

Although bile formation requires that large volumes of water be rapidly transported across liver epithelia, including hepatocytes, the molecular mechanisms by which water is secreted into bile are obscure. The aquaporins are a family of 10 channel-forming, integral membrane proteins of approximately 28 kDa numbered 0-9 that allow water to rapidly traverse epithelial barriers in several organs including kidney, eye, and brain. We found transcripts of three of 10 aquaporins in hepatocytes (aquaporin 8 aquaporin 9 > aquaporin 0) by reverse transcription-polymerase chain reaction and quantitative ribonuclease protection assays; immunohistochemistry confirmed the presence of these three proteins in liver. Immunoblots of subcellular fractions of hepatocytes showed enrichment of aquaporins 0 and 8 in microsomes and canalicular plasma membranes; aquaporin 9 was enriched only in basolateral plasma membranes. Immunofluorescence of hepatocyte couplets confirmed the intracellular/canalicular localization of aquaporins 0 and 8 and the basolateral localization of aquaporin 9. Upon exposure of couplets to a choleretic stimulus (i.e. dibutyryl cAMP), aquaporin 8 redistributed to the canalicular plasma membrane; the subcellular distributions of aquaporins 0 and 9 were unaffected. In addition, exposure of couplets to dibutyryl cAMP caused an increase in canalicular water transport in the presence and absence of an osmotic gradient, an effect that was blocked by aquaporin inhibitors. These results provide evidence that aquaporins are present in hepatocytes and that aquaporins are involved in agonist-stimulated canalicular bile secretion.
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PMID:Expression and localization of aquaporin water channels in rat hepatocytes. Evidence for a role in canalicular bile secretion. 1193 60

The expression and localization of the aquaporin-1 (AQP1) water channel were examined in the glomeruli of the human kidney. A ribonuclease protection assay showed the expression of AQP1 mRNA in human glomeruli but not in rat glomeruli. Western blot analysis revealed 28 kDa and 35 kDa bands corresponding to unglycosylated and glycosylated AQP1 proteins in human glomeruli. Immunoreactive AQP1 was demonstrated almost exclusively in the mesangium in the human glomeruli by immunohistochemistry. The endothelium of glomerular capillaries was only partly immunostained while podocytes and Bowman's capsule epithelia were not immunolabeled. Immunoelectron microscopy localized the immunoreactive AQP1 on the plasma membrane of mesangial cells in human glomeruli. The immouno-gold labeling was dense on the projections of mesangial cells protruding to the glomerular capillary lumen or to endothelial cells, but was sparse on other parts of the mesangial cell surface. No immunoreactivity for AQP1 was demonstrated in rat glomeruli. This study showed the distinct localization of AQP1 in the mesangial cells of human glomeruli, suggesting its role in water movement through these cells.
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PMID:Localization and expression of the aquaporin-1 water channel in mesangial cells in the human glomerulus. 1200 13

A ribonuclease (RNase), exhibiting a molecular mass of 28 kDa and specificity toward polyU and polyA and possessing an N-terminal sequence dissimilar to previously reported mushroom RNases, was isolated from dried fruiting bodies of veiled lady mushroom (Dictyophora indusiata). It demonstrated an RNase activity of 564 U/mg toward yeast transfer RNA. The RNase was adsorbed on DEAE-cellulose, CM-Sepharose, and Q-Sepharose. It demonstrated a pH optimum of 4-4.5 and a temperature optimum of 60 degrees C. There was a loss of RNase activity at temperatures above 60 degrees C.
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PMID:A novel ribonuclease from the veiled lady mushroom Dictyophora indusiata. 1466 3

A psychrotrophic bacterium Shewanella sp. strain SIB1 was grown at 4 and 20 degrees C, and total soluble proteins extracted from the cells were analyzed by two-dimensional polyacrylamide gel electrophoresis. Comparison of these patterns showed that the cellular content of a protein with a molecular mass of 28 kDa and an isoelectric point of four greatly increased at 4 degrees C compared to that at 20 degrees C. Determination of the N-terminal amino acid sequence, followed by the cloning and sequencing of the gene encoding this protein, revealed that this protein is a member of the FKBP family of proteins with an amino acid sequence identity of 56% to Escherichia coli FKBP22. This protein was overproduced in E. coli in a His-tagged form, purified, and analyzed for peptidyl-prolyl cis-trans isomerase activity. When this activity was determined by the protease coupling assay using N-succinyl-Ala-Leu-Pro-Phe-p-nitroanilide as a substrate at various temperatures, the protein exhibited the highest activity at 10 degrees C with a k(cat)/K(m) value of 0.87 micro m(-1) x s(-1). When the peptidyl-prolyl cis-trans isomerase activity was determined by the RNase T(1) refolding assay at 10 and 20 degrees C, the protein exhibited higher activity at 10 degrees C with a k(cat)/K(m) value of 0.50 micro m(-1) x s(-1). These k(cat)/K(m) values are lower but comparable to those of E. coli FKBP22. We propose that a FKBP family protein is involved in cold-adaptation of psychrotrophic bacteria.
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PMID:Possible involvement of an FKBP family member protein from a psychrotrophic bacterium Shewanella sp. SIB1 in cold-adaptation. 1503 Apr 88

The most abundant root proteins of ginseng (Panax ginseng) have been detected and identified by comparative proteome analysis with cultured hairy root of ginseng. Four abundant proteins (28, 26, 21 and 20 kDa) of P. ginseng had isoforms with different pl values on two-dimensional gel electrophoresis (2DE). The results of N-terminal and internal amino acid sequencing, however, showed that all of them originate from a 28 kDa protein, known as ginseng major protein (GMP). The GMP gene was searched for in the expressed sequence tag database of P. ginseng and found to encode a 27.3 kDa protein having 238 amino acid residues. Analysis of the amino acid sequences indicates that GMP exhibits high sequence homology with plant RNases and RNase-like proteins. However, purified GMP had no RNase activity even though it has conserved amino acid residues known to be essential for active sites of RNase. The GMPs present in ginseng main root were not expressed in cultured hairy roots of ginseng. 2DE analysis showed that the amounts of GMPs in main roots change according to seasonal fluctuation. These results suggest that the GMPs are root-specific RNase-like proteins, which function as vegetative storage proteins of ginseng for survival in the natural environment.
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PMID:Characterization of RNase-like major storage protein from the ginseng root by proteomic approach. 1531 73

A protease was purified from fresh fruiting bodies of the edible mushroom Pleurotus citrinopileatus. The isolation procedure included ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-Sepharose and fast protein liquid chromatography-gel filtration on Superdex 75. The protease was unadsorbed on DEAE-cellulose and Q-Sepharose, but adsorbed on CM-cellulose. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the protease demonstrated a single band with a molecular mass of 28 kDa. The protease showed an optimal pH at 10 and an optimal temperature at 50 degrees C. The activity of the protease was not affected by EDTA, indicating that it is not a metalloprotease. The protease exhibited a higher activity in the presence of K(+) and Li(+), but its activity was potently inhibited by Al(3+), Cu(2+), and Hg(2+) ions. It manifested a K (m) of 3.44 mg/ml and a V (max) of 0.139 mg ml(-1) min(-1). It was devoid of ribonuclease and antifungal activities.
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PMID:An alkaline protease from fresh fruiting bodies of the edible mushroom Pleurotus citrinopileatus. 1721 42

Antitumor ribonucleases are small (10-28 kDa) basic proteins. They were found among members of both, ribonuclease A and T1 superfamilies. Their cytotoxic properties are conferred by enzymatic activity, i.e., the ability to catalyze cleavages of phosphodiester bonds in RNA. They bind to negatively charged cell membrane, enter cells by endocytosis and translocate to cytosol where they evade mammalian protein ribonuclease inhibitor and degrade RNA. Here, we discuss structures, functions and mechanisms of antitumor activity of several cytotoxic ribonucleases with particular emphasis to the amphibian Onconase, the only enzyme of this class that reached clinical trials. Onconase is the smallest, very stable, less catalytically efficient and more cytotoxic than most RNase A homologues. Its cytostatic, cytotoxic and anticancer effects were extensively studied. It targets tRNA, rRNA, mRNA as well as the non-coding RNA (microRNAs). Numerous cancer lines are sensitive to Onconase; their treatment with 10-100 nM enzyme leads to suppression of cell cycle progression, predominantly through G(1), followed by apoptosis or cell senescence. Onconase also has anticancer properties in animal models. Many effects of this enzyme are consistent with the microRNAs, one of its critical targets. Onconase sensitizes cells to a variety of anticancer modalities and this property is of particular interest, suggesting its application as an adjunct to chemotherapy or radiotherapy in treatment of different tumors. Cytotoxic RNases as exemplified by Onconase represent a new class of antitumor agents, with an entirely different mechanism of action than the drugs currently used in the clinic. Further studies on animal models including human tumors grafted on severe combined immunodefficient (SCID) mice and clinical trials are needed to explore clinical potential of cytotoxic RNases.
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PMID:Ribonucleases as potential modalities in anticancer therapy. 1982 71


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