Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RNAse”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed2006

Cloning and characterization of an RNase-related protein gene preferentially expressed in rice stems.

RNase-related proteins (RRPs) are S- and S-like RNase homologs lacking the active site required for RNase activity. Here we describe the cloning and characterization of the rice (Oryza sativa) RRP gene (OsRRP). A single copy of OsRRP occurs in the rice genome. OsRRP contains three introns and an open reading frame encoding 252 amino acids, with the replacement of two histidines involved in the active site of RNase by lysine and tyrosine respectively. OsRRP is preferentially expressed in stems of wild-type rice and is significantly down-regulated in an increased tillering dwarf mutant ext37.

Amino Acid Sequence↗
PubMed2005

A novel endoribonuclease, RNase LS, in Escherichia coli.

The dmd gene of bacteriophage T4 is required for the stability of late-gene mRNAs. When this gene is mutated, late genes are globally silenced because of rapid degradation of their mRNAs. Our previous work suggested that a novel Escherichia coli endonuclease, RNase LS, is responsible for the rapid degradation of mRNAs. In this study, we demonstrated that rnlA (formerly yfjN) is essential for RNase LS activity both in vivo and in vitro. In addition, we investigated a role of RNase LS in the RNA metabolism of E. coli cells under vegetative growth conditions. A mutation in rnlA reduced the decay rate of many E. coli mRNAs, although there are differences in the mutational effects on the stabilization of different mRNAs. In addition, we found that a 307-nucleotide fragment with an internal sequence of 23S rRNA accumulated to a high level in rnlA mutant cells. These results strongly suggest that RNase LS plays a role in the RNA metabolism of E. coli as well as phage T4.

Bacteriophage T4↗
PubMed1998

II. Electrostatic effect in the aggregation of heat-denatured RNase A and implications for protein additive design.

In the previous study (part I), heat-denatured RNase A aggregation was shown to depend on the solution pH. Interestingly, at pH 3.0, the protein did not aggregate even when exposed to 75 degrees C for 24 h. In this study, electrostatic repulsion was shown to be responsible for the absence of aggregates at that pH. While RNase A aggregation was prevented at the extremely acidic pH, this is not an environment conducive to maintaining protein function in general. Therefore, attempts were made to confer electrostatic repulsion near neutral pH. In this study, heat-denatured RNase A was mixed with charged polymers at pH 7.8 in an attempt to provide the protein with excess surface cations or anions. At 75 degrees C, SDS and dextran sulfate were successful in preventing RNase A aggregation, whereas their cationic, nonionic, and zwitterionic analogs did not do so. We believe that the SO3- groups present in both additives transformed the protein into polyanionic species, and this may have provided a sufficient level of electrostatic repulsion at pH 7.8 and 75 degrees C to prevent aggregation from proceeding.

Hot Temperature↗
PubMed1999

Luteinizing hormone releasing hormone-RNase A conjugates specifically inhibit the proliferation of LHRH-receptor-positive human prostate and breast tumor cells.

Human prostate and breast tumor cells produce luteinizing hormone-releasing hormone (LHRH) receptors on their cell surface even when they have lost dependency on sex steroid hormones for growth. To investigate whether LHRH can be used as a cell-binding moiety to deliver toxin molecules into prostate and breast tumor cells, LHRH-bovine RNase A conjugates were constructed using the chemical cross-linking method. The treatment of the LHRH receptor-positive cells such as prostate LNCapFGC and breast MCF7 tumor cells with LHRH-RNase A conjugates resulted in a dose-dependent inhibition of growth. The cytotoxic activities of these conjugates were effectively reduced by the presence of exogenous LHRH. Either free RNase A or LHRH alone did not affect the proliferation of these cells. The LHRH-RNase A conjugates did not show cytotoxicity against FRTL5 and TM4 cells which do not express the LHRH receptors. These results suggest that LHRH can be used as a cell-binding molecule for the specific delivery of toxin molecules into the cells which express LHRH receptors on their surface. Thus, a new class of biomedicines that act as fusion proteins between LHRH and toxins will give us a new avenue for the treatment of human prostate and breast cancers, regardless of their steroid hormone dependency.

Breast Neoplasms↗
PubMed1999

Molecular evaluation of bone marrow involvement in peripheral T-cell lymphoma with a PCR-mediated RNase protection assay.

Bone marrow (BM) involvement in peripheral T-cell lymphoma was assessed by polymerase chain reaction (PCR)-mediated RNase protection assay. The sensitivity of this assay was approximately 10(-4) to 10(-5). In 16 of 30 patients (53.3%) with peripheral T-cell malignancies, consensus primers for the T-cell receptor (TCR)-gamma gene amplified the rearranged V(N)J region. Using the PCR products of diagnostic lymph nodes of the patients as probes, we analyzed the BM involvement of lymphoma cells in eight patients: four with peripheral T-cell lymphoma, unspecified; two with adult T-cell leukemia/lymphoma; and two with angioimmunoblastic T-cell lymphoma. BM involvement was detected by PCR-mediated RNase protection assay in four patients from BM smear and/or histo-pathological examination of clotted BM. Moreover, in two of four patients in whom BM involvement was not evident from morphological examination, BM involvement was detected by PCR-mediated RNase protection assay. Our results indicate that the PCR-mediated RNase protection assay targeting the TCR-gamma gene is useful in detecting minimal residual disease in about half of all T-cell lymphoma cases. In addition, in some patients with peripheral T-cell lymphoma, morphologically unproven BM involvement was found using the method.

Adult↗
PubMed1992

Sequence and transcriptional analysis of the Escherichia coli rnt gene encoding RNase T.

The Escherichia coli rnt gene encoding the enzyme RNase T, which is responsible for the end-turnover of tRNA, was cloned on a 1.5-kilobase DNA fragment. When placed in pUC18 and pUC19 vectors this fragment led to approximately a 40-fold overexpression of RNase T activity. The cloned fragment was sequenced and was found to contain an open reading frame sufficient to encode a protein of 215 amino acids with a molecular weight of 23,521, which is close to the subunit molecular weight of RNase T; the fragment also contains a second incomplete open reading frame with some sequence similarity to RNA helicases. The derived sequence of RNase T showed no similarity to any of the other E. coli exoribonucleases sequenced to date. Primer extension analysis and deletion of part of the upstream region were used to identify the transcription start point and the promoter of the rnt gene. Northern and primer extension analysis revealed that the rnt message also included the second open reading frame, suggesting that rnt is part of an operon.

Amino Acid Sequence↗
PubMed2006

Some biological actions of PEG-conjugated RNase A oligomers.

Previously we have shown that monomeric RNase A has no significant biological activity, whereas its oligomers (dimer to tetramer) prepared by lyophilizing from 50% acetic acid solutions, show remarkable aspermatogenic and antitumor activities. Furthermore, conjugates prepared by chemical binding of native RNase A to polyethylene glycol (PEG) have shown a significant aspermatogenic and antitumor activities. In this work we show that the chemical conjugation of PEG to the RNase A C-dimer, and to the two RNase A trimers (NC-trimer and C- trimer) decreases the aspermatogenic activity of the oligomers while increasing their inhibitory activity on the growth of the human UB900518 amelanotic melanoma transplanted in athymic nude mice. Moreover, the PEG-conjugated RNaseA oligomers are devoid, like the free oligomers, of any embryotoxic activity.

Animals↗
PubMed1991

Coupling of reverse transcriptase and RNase H during HIV-1 replication.

The retroviral replicating enzyme reverse transcriptase (RT) is associated with an RNase H which specifically hydrolyzes RNA in RNA-DNA hybrids. The RNase H exhibits endo- as well as exonuclease activity when analyzed with in vitro synthesized viral RNA hybridized to a shorter synthetic DNA oligonucleotide. In the presence of deoxyribonucleotides the RT synthesizes DNA in a concerted action with the RNase H, which simultaneously hydrolyzes the RNA template. Mutants of the RNase H derived by site-directed mutagenesis of a conserved histidine 539 are preferentially impaired in their exo- and less in their endonuclease activity. A specific polypurine-rich oligonucleotide created at the polypurine tract (PPT), serves as a primer for plus-strand DNA synthesis. Initiation of DNA synthesis at the PPT-primer can be demonstrated for the wt enzyme in vitro in contrast to the mt enzymes which do not recognize this sequence. A replication model based on these results is presented.

Base Sequence↗
PubMed1989

Analysis of the upstream region of the Escherichia coli rnd gene encoding RNase D. Evidence for translational regulation of a putative tRNA processing enzyme.

The upstream region of the Escherichia coli rnd gene has been analyzed. A single promoter and transcription start site were identified in the 170-nucleotide upstream region of the clone based on deletion analysis, nuclease S1 mapping, primer extension, and quantitative dot-blots. The start site of transcription is 70 nucleotides upstream of the UUG initiation codon of the RNase D coding region. Between the RNA initiation site and the coding region is a GC-rich hairpin structure followed by 8 T residues that looks like a rho-independent transcription terminator. Surprisingly, deletion of the hairpin structure elevates rnd mRNA levels only slightly (less than 2-fold), but it dramatically decreases RNase D expression (greater than 95%), measured both by activity and immunoblotting. No evidence for an effect on mRNA stability or processing was observed. The uncommon UUG translation initiation codon was converted to AUG by site-directed mutagenesis. This alteration led to an 11-fold elevation of RNase D expression in single-copy plasmids. These data indicate that RNase D expression is negatively regulated at the translational level by the initiation codon, and that an upstream structure (or sequence) also influences translation of this gene.

Base Sequence↗
PubMed1985

Respective role of each of the purine N-6 amino groups of 5'-O-triphosphoryladenylyl(2'----5')adenylyl(2----5')adenosine in binding to and activation of RNase L.

We have synthesized a series of 2-5A (ppp5'-A2'p5'A2'p5'A) analogs in which each adenosine residue has been sequentially replaced by inosine: viz., ppp5'I2'p5'A2'p5'A, ppp5'A2'p5'I2'p5'A, and ppp5'A2'p5'A2'p5'I. These transformations enabled us to delineate the role of each of the three purine N-6 amino groups of 2-5A in determining oligonucleotide binding to and activation of the 2-5A-dependent endoribonuclease, RNase L. With the RNase L activity of both mouse L cells and human Daudi lymphoblastoid cells, we found that the N-6 amino group of the first adenosine nucleotide residue (from the 5'-terminus) is of crucial importance in determining binding to the endonuclease; however, removal of the N-6 amino moieties of the second or third adenosine nucleotide residues resulted in only a minimal decrease in binding to the endonuclease. On the other hand, conversion of the third adenosine residue to inosine effected a dramatic (10,000-fold compared to 2-5A) loss in ability to activate the nuclease; however, execution of the same N-6 amino group conversion at either the first or second adenosine residue did not cause a major change in nuclease activation ability when the accompanying decreased endonuclease binding was considered. These results clearly demonstrate that the N-6 amino group of the first adenosine residue of 2-5A is critical in RNase L binding whereas the N-6 amino function of the third adenosine residue of 2-5A is crucial for the activation of RNase L.

Adenine Nucleotides↗
PubMed1977

Purification and some novel properties of Escherichia coli RNase II.

RNase II of Escherichia coli (EC 3.1.4.23) has been purified to apparent homogeneity. The K+-activated diesterase activity against poly(U), which defines RNase II, cochromatographs with activity against T4 mRNA or pulse-labeled E. coli RNA successively on DEAE-cellulose, hydroxyapatite or phosphocellulose, and Sephadex G-150 columns. Activities with both substrates are selectively reduced to less than 2% of the wild type level in a newly isolated mutant strain, S296, or after thermal inactivation in a mutant strain with temperature-sensitive RNase II. RNase II releases 5'-XMP without a lag as its only detectable alcohol-soluble produce from all substrates and has an apparent molecular weight of 80,000 to 90,000 in both nondissociating and sodium dodecyl sulfate-polyacrylamide gels. The pure enzyme shows the standard K+ activation against poly(A), poly(U), or poly(C), but only a slight preference for K+ over Na+ ions with T4 mRNA or pulse labeled E. coli RNA as substrate. Uniformly labeled E. coli rRNA or tRNA is degraded little if at all.

Enzyme Activation↗
PubMed1988

Purification and analysis of murine 2-5A-dependent RNase.

2-5A-dependent RNase (RNase L, RNase F) is an enzyme which mediates effects of 2-5A (px(A2'p)nA; x = 2 or 3, n greater than or equal to 2) in cells. 2-5A binding activity present in mouse liver extracts was measured using a 32P-labeled 2-5A derivative. Analysis of Scatchard plots was consistent with a single noninteracting 2-5A binding site with a Ka of 2.5 X 10(10) M-1. Similarly, affinity labeling of proteins with a 32P-labeled 2-5A derivative revealed a single, high-affinity 2-5A-binding protein of Mr 80,000. This 2-5A-binding protein was the only mouse liver protein specifically and consistently eluted by 2-5A from an affinity resin consisting of core(2-5A) covalently attached to cellulose. The 2-5A-eluted protein could degrade polyuridylic acid but not polycytidylic acid. Furthermore, when the 2-5A-eluted protein was electrophoresed into a polyuridylic acid-containing, nondenaturing gel, a band of degraded polyuridylic acid was demonstrated after incubation with 2-5A. There was no band of degraded polyuridylic acid when the elution was performed either in the absence of oligonucleotide or in the presence of low amounts of a closely related analog of 2-5A, p3I2'pA2'pA. Therefore, the Mr 80,000 2-5A-binding protein and the 2-5A-dependent RNase were almost certainly the same protein. Finally, the Mr 80,000 2-5A-binding protein was purified to homogeneity by electroelution from a polyacrylamide gel.

Animals↗
PubMed1986

[Experimental study of the allergenic and modulating properties of RNAses].

It was shown with the immediate type hypersensitivity (ITH) test and the delayed type hypersensitivity (DTH) test that pancreatic RNase and RNases from Bacillus sp. had rather pronounced allergenic properties which were similar in both the tests. The modulating properties of the RNases with respect to sensitization in accordance with ITH or DTH were also investigated. It was shown that the enzymes did not influence development of ITH in the experimental animals sensitized with the BCA vaccine. However, they markedly increased DTH in the experimental animals sensitized with the BCG vaccine. RNase from Bacillus sp. selectively inactivated with respect to histidine of the active site maintained its capacity for increasing DTH when used as a native enzyme.

Adjuvants, Immunologic↗
PubMed1986

[Multiplicity of affinity modification of RNAse during its alkylation with a reactive analog of 5-deoxyribonucleotide].

The interaction of pancreatic RNase with 5'-deoxyribodinucleotide alkylating derivative, 4-(N-2-chloroethyl-N-methylamino)benzylamide of d(pTpA) d[(ClRCH2NH)pTpA], was studied. The unreactive oxyanalogue d[(HORCH2NH)pTpA] was shown to act as competitive inhibitor of cCMP hydrolysis by RNase. d[(ClRCH2NH)pTpA] irreversibly inactivated RNase. A protective effect was exerted by d(pTpA) and d[(HORCH2NH)pTpA]. The modification, although having an affinity character, was not accompanied by total inactivation of the enzyme. It was supposed that covalent bonding between the reagent and enzyme induced the dinucleotide displacement from the recognition site. The formation of four RNase monolabeled forms retaining the activity in the hydrolysis of cCMP and poly(U) was demonstrated.

Alkylating Agents↗
PubMedDate not supplied

[Influenza inhibitor of the host serum RNAse].

From soluble proteins of influenza A viruses the author isolated, partially purified, and concentrated an inhibitor of host serum RNase, possessing no infectivity or neuraminidase activity, having the virus-specific antigen and, apparently, a lipoprotein composition, inhibiting RNAse activity by forming a complex with the enzyme and substrate, and considered to be one of the factors of virus pathogenicity acting on the molecular level. Antigenic relationships between RNase inhibitors of hierarchically remote influenza viruses were found. Immunization of mice with the inhibitor antigen prevents inhibition of serum RNAse activity after infection, and vaccination with the inhibitor antigen in combination with whole-virion killed vaccine significantly increased the protective effectiveness of the artificial immunity in experiments. The inhibitor preparation obtained is anaphylactogenic.

Animals↗
PubMed1985

Ion dependence of the Bacillus subtilis RNase P reaction.

The properties of the Bacillus subtilis RNase P are characterized with regard to the types and concentrations of monovalent and divalent ions required to potentiate precursor tRNA cleavage by the protein-RNA holoenzyme and the catalytic RNA alone. The ionic dependence of the RNase P RNA-catalyzed reaction in part seems due to a requirement for ion shielding between substrate and catalytic RNAs. The RNase P protein, which binds to RNA nonspecifically and tightly, likely serves, in part, as a cation screen. However, the character of the ion dependence of the RNA catalysis, the inhibition by high SO2-4 concentration, and potentiation by solvents suggest that RNA conformational transition may be involved in the reaction. It is proposed that the reason for catalysis by RNA in the RNase P reaction may be a requirement for fluidity in the structure of the catalyst, so that it can accommodate many tRNA substrates, which vary in their structural details.

Bacillus subtilis↗
PubMed1982

[Antitumor action of RNAses modified by covalent binding with dextran m-aminobenzylhydroxymethyl ether].

Antitumor effect of pancreatic RNase and RNase from Actinomyces rimosus, as well as of their derivatives modified by dextran m-aminobenzylhydroxymethyl ether under different conditions was studied and compared. It was found that the efficacy of actinomycetous enzyme and its modified derivatives was superior to that of the analogous preparations of pancreatic RNase. Antitumor effect of the modified enzymes was higher than that of the native ones and depended on the modification conditions. It is concluded that biological efficacy of the RNases is determined by their origin and physico-chemical properties.

Animals↗
PubMed1982

[Antiviral activity of modified RNAses].

Antiviral activity of pancreatic RNase and RNase from Act.rimosus modified by various dextran derivatives was studied with respect to aphthosa and Ayzeku disease viruses. Antiviral activity of pancreatic RNase modified by dextran m-aminobenzylhydroxymethyl ether was lower than biological activity of RNase from Act.rimosus modified by the same dextran. Antiviral activity of pancreatic enzyme modified by dialdehyde dextran also changed insignificantly. Modification by dextran hydroxyethylsulfonylanisole ether, dextran m-aminobenzylhydroxymethyl ether in the presence of pyridine or dextran sulfate resulted in a more pronounced increase in antiviral activity of pancreatic enzyme. Therefore, biological activity of the modified nucleases depended on the nature of the enzyme and dextran modifying it.

Animals↗