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)

Crude extracts from Escherichia coli were screened for any broad-specificity endoribonuclease after the cell proteins were fractionated by size. In a mutant lacking the gene for RNase I (molecular mass, 27,156 Da), the only such activities were also in the size range of 23 to 28 kDa. Fractionation by chromatography on a strong cation-exchange resin revealed only two activities. One of them eluted at a salt concentration expected for RNase M and had the specificity of RNase M. It preferred pyrimidine-adenosine bonds, could not degrade purine homopolymers, and had a molecular mass of approximately 27 kDa (V. J. Cannistraro and D. Kennell, Eur. J. Biochem. 181:363-370, 1989). A second fraction, eluting at a higher salt concentration, was active against any phosphodiester bond but was about 100 times less active than are RNase I and RNase I* (a form of RNase I) in the wild-type cell. On the basis of sizing-gel chromatography, this enzyme had a molecular mass of approximately 24 kDa. We call it RNase R (for residual). RNase R is not an abnormal product of the mutant rna gene; a cell carrying many copies of that gene on a plasmid did not synthesize more RNase R. Our search for broad-specificity endoribonucleases was prompted by the expectation that the primary activities for mRNA degradation are expressed by a relatively small number of broad-specificity RNases. If correct, the results suggest that the endoribonucleases for this major metabolic activity reside in the 24- to 28-kDa size range. Endoribonucleases with much greater specificity must have as primary functions the processing of specific RNA molecules at a very limited number of sites as steps in their biosynthesis. In exceptional cases, these endoribonucleases inactivate a specific message that has such a site, and they can also effect total mRNA metabolism indirectly by a global disturbance of the cell physiology. It is suggested that a distinction be made between these processing and degradative activities.
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PMID:Broad-specificity endoribonucleases and mRNA degradation in Escherichia coli. 130 22

Less purified fractions of ribonuclease H IIa activity of calf thymus display divalent cation-dependent ribonuclease H activity and divalent cation-independent ribonuclease activity. Because the ratio of the two enzyme activities does not change during successive chromatographic procedures, we suggest that ribonuclease H IIa activity is indeed able to degrade both ssRNA and the RNA moiety of RNA.DNA-hybrids. Ribonuclease H IIa activity can therefore be differentiated from calf thymus ribonuclease H I and H IIb by its lack of ribonuclease H specificity. The native molecular mass of ribonuclease H IIa activity is between 23 and 28 kDa. Under denaturing conditions a 23 kDa-protein band copurifies with the enzyme activity suggesting that this enzyme is monomeric.
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PMID:Calf thymus ribonuclease H IIa activity lacks ribonuclease H specificity. 169 Jan 46

To begin the process of identification and charactization of rat ovarian insulin-like growth factor binding proteins, we have undertaken to explore the ovarian expression, cellular localization, and hormonal regulation of the insulin-like growth factor binding protein-2 (IGFBP-2) gene for which an antigonadotropic potential has recently been demonstrated. To this end, a solution hybridization/RNase protection assay was employed wherein total ovarian RNA (20 micrograms) from immature (21-23 days old) female rats was hybridized with a [32P]-labeled IGFBP-2 riboprobe. As in liver, a single protected fragment (550 bases long) corresponding to IGFBP-2 transcripts was identified in whole ovarian material. Cellular localization studies revealed the IGFBP-2 gene to be exclusively expressed in the theca-interstitial rather than the granulosa cell compartment. To confirm the cellular distribution of the IGFBP-2 protein, media conditioned by cultured granulosa or theca-interstitial cells were subjected to immunoprecipitation using two IGFBP-2-directed polyclonal antisera. Expectedly, both antibodies (but not non-immune rabbit serum) readily immunoprecipitated the 28 kDa rat IGFBP-2 species generated by hepatic BRL-3A cells. Similarly, both antibodies effectively immunoprecipitated an IGFBP the size of rat IGFBP-2 elaborated by theca-interstitial cells. In contrast, neither antibody immunoprecipitated the 28-29 kDa IGFBP species elaborated by granulosa cells otherwise readily apparent in conventional Western ligand blots. Hypophysectomy resulted in a 3-fold decrease (P less than 0.05) in the relative (densitometrically-quantified) abundance of ovarian IGFBP-2 transcripts, a diametrically opposed effect (P less than 0.05) being noted at the level of the liver. In contrast, treatment of immature hypophysectomized rats with a diethylstilbestrol-containing subcutaneous silastic implant for a total of 5 days resulted in a concordant 3-fold increase (P less than 0.05) in the relative abundance of IGFBP-2 transcripts in both ovary and liver when compared with untreated hypophysectomized controls. Taken together, these findings document rat ovarian IGFPB-2 gene expression to be theca-interstitial (rather than granulosa) cell-selective, and subject to upregulatory control by pituitary principle(s) and/or by estrogens. Although equally estrogen-dependent, hepatic IGFBP-2 gene expression proved constitutive in nature and subject to (diametrically opposed) inhibitory control by (potentially distinct) pituitary principle(s).
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PMID:The ovarian expression of the antigonadotropic insulin-like growth factor binding protein-2 is theca-interstitial cell-selective: evidence for hormonal regulation. 171 46

The relationship between the antigenic proteins of Sm and RNP is not clear. To further clarify their relationship, we examined sera found monospecific by counterimmunoelectrophoresis (CIEP) for anti-Sm or anti-RNP with the more sensitive techniques of immunoblotting, radioimmunoprecipitation, or enzyme immunoassay (EIA). The same eight unique problems were precipitated by both anti-Sm and anti-RNP in radioimmunoprecipitation. They had molecular weights (MWs) of 11, 13, 17, 18, 24, 26, 28, and 68 kDa. The 17, 18, and 28 kDa bands were more intense with anti-RNP. Immunoblotting with anti-Sm and anti-RNP also recognized similar proteins with MWs of 14, 17, 25, 28, 29, 30, 36, 38, and 68 kDa. Anti-Sm resulted in more intense 14, 28, 29, and 30 kDa bands, while anti-RNP gave maximum intensity of the 14, 36, 38, and 68 kDa bands. The band intensity pattern differences were more easily appreciated with immunoblotting than with radioimmunoprecipitation. RNase, heat, and urea caused a similar diminution of antigen reactivity with both anti-Sm and anti-RNP on immunoblotting, but eliminated immunoprecipitability only of RNP on immunodiffusion. The great similarities between Sm and RNP suggest several possibilities: Anti-Sm and anti-RNP antibodies coexist in the same patients; and the more sensitive techniques of immunoblotting and radioimmunoprecipitation detect both precipitating and nonprecipitating antibodies while only precipitating antibodies are detected by immunodiffusion. Sm and RNP may represent different determinants on the same macromolecular complex. Sm and RNP may be cross-reacting determinants on distinct molecules.
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PMID:The relationship between Sm and RNP antigens. 242 69

The aquaporins transport water through membranes of numerous tissues, but the molecular mechanisms for sensing changes in extracellular osmolality and regulating water balance in brain are unknown. We have isolated a brain aquaporin by homology cloning. Like aquaporin 1 (AQP1, also known as CHIP, channel-forming integral membrane protein of 28 kDa), the deduced polypeptide has six putative transmembrane domains but lacks cysteines at the known mercury-sensitive sites. Two initiation sites were identified encoding polypeptides of 301 and 323 amino acids; expression of each in Xenopus oocytes conferred a 20-fold increase in osmotic water permeability not blocked by 1 mM HgCl2, even after substitution of cysteine at the predicted mercury-sensitive site. Northern analysis and RNase protection demonstrated the mRNA to be abundant in mature rat brain but only weakly detectable in eye, kidney, intestine, and lung. In situ hybridization of brain localized the mRNA to ependymal cells lining the aqueduct, glial cells forming the edge of the cerebral cortex and brainstem, vasopressin-secretory neurons in supraoptic and paraventricular nuclei of hypothalamus, and Purkinje cells of cerebellum. Its distinctive expression pattern implicates this fourth mammalian member of the aquaporin water channel family (designated gene symbol, AQP4) as the osmoreceptor which regulates body water balance and mediates water flow within the central nervous system.
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PMID:Molecular characterization of an aquaporin cDNA from brain: candidate osmoreceptor and regulator of water balance. 752 31

A ribonuclease (RNase Oy) was purified to homogeneity on SDS-PAGE from the homogenate of oyster (Crussdstrea grigus). The apparent molecular weight estimated from SDS-PAGE was ca. 28 kDa. The pH optimum of the RNase was 5.0. The RNase released mononucleotides from RNA in the order of 3'-GMP, 3'-AMP, and 3'-UMP. The complete amino acid sequence of RNase Oy was determined, mostly by analyzing the peptides generated by BrCN cleavage or digestion by lysylendopeptidase, staphylococcal V8 protease, and alpha-chymotrypsin. The molecular weight of the protein moiety of RNase Oy deduced from the sequence was 24,359. The sequence of RNase Oy contained two typical histidine residues in segments common to the active site of RNase T2 family enzymes. The locations of six half cystine residues among eight were almost superimposable on those of four known plant RNases of RNase T2 family. The sequence homology between RNase Oy and five fungal and four plant RNases amount, to 43-56 amino acid residues. The amino acid sequence of the N-terminal part of RNase Oy is more similar to those of plant RNases than to those of fungal RNases. This RNase is the first RNase T2 family RNase from mollusc whose primary structure has been elucidated.
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PMID:Purification, some properties, and primary structure of a base non-specific ribonuclease from oyster (Crussdstrea grigus). 813 35

Stylar proteins of 13 almond (Prunus dulcis) cultivars with known S-genotypes were surveyed by IEF and 2D-PAGE combined with immunoblot and N-terminal amino acid sequence analyses to identify S-RNases associated with gametophytic self-incompatibility (SI) in this plant species. RNase activities corresponding to Sa and Sb, two of the four S-alleles tested, were identified by IEF and RNase activity staining. The Sa-RNase band reacted with the anti-S4-serum prepared from Japanese pear (Pyrus serotina); no reaction with the antiserum was observed with the Sb-RNase band. When the Sa-RNase band was excised from an IEF gel stained for RNase activity, subjected to SDS-PAGE, and detected by immunoblotting, it appeared that this band consisted of a single protein that reacted with the anti-S4-serum with M(r) of about 28 kDa. With 2D-PAGE and silver staining of the stylar extracts, all four S-proteins could be successfully distinguished from each other in the highly basic zone of the gel. Although Sb-, Sc-, and Sd-proteins had roughly the same M(r) of about 30 kDa, the Sc-protein seemed to be slightly smaller than the Sb-protein and slightly larger than the Sd-protein. In 2D-PAGE profiles as well, the Sa-protein had M(r) of about 28 kDa, apparently smaller than the other three proteins. A bud sport, in which one of the two S-alleles of the original cultivar is impaired, was visualized as a loss of Sc-protein, which is consistent with the previous pollination study. All four S-proteins reacted with the anti-S4-serum, probably because of the differing conformations of these S-proteins in the IEF and 2D-PAGE gels. The Sa-protein in 2D-PAGE appeared to be identical to Sa-RNase in IEF; both had the same M(r) and were reactive with the anti-S4-serum. N-terminal amino acid sequence analysis of the four S-proteins revealed that they were highly homologous to each other and similar to the S-RNases of Malus, Pyrus, Scrophulariaceae, and Solanaceae. Taken together, RNases in the style are strongly suggested to be associated with the gametophytic SI of almond. This is the first report identifying and characterizing S-RNase in almond.
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PMID:Identification of stylar RNases associated with gametophytic self-incompatibility in almond (Prunus dulcis). 915 Jun 3

We have identified two distinct subunits of 20 S proteasomes that are associated with RNase activity. Proteasome subunits zeta and iota, eluted from two-dimensional Western blots, hydrolysed tobacco mosaic virus RNA, whereas none of the other subunits degraded this substrate under the same conditions. Additionally, proteasomes were dissociated by 6 M urea, and subunit zeta, containing the highest RNase activity, was isolated by anion-exchange chromatography and gel filtration. Purified subunit zeta migrated as a single spot on two-dimensional PAGE with a molecular mass of approx. 28 kDa. Addition of anti-(subunit zeta) antibodies led to the co-precipitation of this proteasome subunit and nuclease activity. This is the first evidence that proteasomal alpha-type subunits are associated with an enzymic activity, and our results provide further evidence that proteasomes may be involved in cellular RNA metabolism.
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PMID:Involvement of proteasomal subunits zeta and iota in RNA degradation. 933 55

Human endometrium is the major organ that produces glycodelin A (GdA). The production of endometrial GdA causes a fluctuation of the peripheral glycodelin concentrations in women during the menstrual cycle and pregnancy. It has recently been reported that the rise of plasma concentrations of glycodelin is correlated with relaxin during the late luteal phase and early pregnancy. In addition, administration of relaxin increases glycodelin plasma concentrations, suggesting that relaxin induces GdA production in endometrium. To investigate whether relaxin regulates the GdA synthesis, human endometrial glandular epithelial cells were isolated and cultured with or without relaxin for up to 4 days. Western blot showed that GdA synthesized and secreted from epithelial glands had a major molecular weight of 28 kDa, i.e. the same as the GdA isolated from amniotic fluid. Cells incubated with relaxin consistently increased in GdA production rate (2-6-fold). The GdA mRNA concentrations increased 2-11-fold in cells incubated with relaxin for 2-4 days, as determined by solution hybridization/ribonuclease protection assay. The increase of the mRNA concentration indicates that relaxin activates GdA transcription.
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PMID:Relaxin stimulates glycodelin mRNA and protein concentrations in human endometrial glandular epithelial cells. 1032 10

An antifungal protein, possessing a molecular weight of 28 kDa and an N-terminal sequence resembling chitinases, has been purified from the seeds of the field bean Dolichos lablab. The procedure involved extraction with aqueous buffer, affinity chromatography on Affi-gel blue gel, and ion exchange chromatography on CM-Sepharose. The protein, designated dolichin, exhibited antifungal activity against the fungi Fusarium oxysporum, Rhizoctonia solani, and Coprinus comatus. Dolichin was capable of inhibiting human immunodeficiency virus (HIV) reverse transcriptase and alpha- and beta-glucosidases which are glycohydrolases implicated in HIV infection. It had very low ribonuclease and cell-free translation-inhibitory activities.
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PMID:Dolichin, a new chitinase-like antifungal protein isolated from field beans (Dolichos lablab). 1069 93


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