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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The sequences of the first 17 nucleotides of cowpea mosaic virus middle and bottom RNAs adjacent to the covalently-linked proteins have been determined. Sequences of the oligonucleotides, produced by complete T1 RNase digestion, were established after labelling of the 3' termini in vitro using RNA ligase. Both sequences are A/U-rich, the first nine nucleotides being identical.
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PMID:Nucleotide sequences adjacent to the proteins covalently linked to the cowpea mosaic virus genome. Sequence determination after labelling in vitro using RNA ligase. 11 52

RNA ligase has been highly purified in good yields from bacteriophage T4-infected Escherichia coli by a rapid and reproducible procedure. The enzyme is free of phosphomonoesterase and ribonuclease activities and is therefore suitable for the synthesis of oligoribonucleotides and for the labeling of the 3'-terminus of RNA. Greater than 90% of the protein in the enzyme preparation migrates as a single band on gradient polyacrylamide gels containing sodium dodecyl sulfate during electrophoresis. For use as a DNA synthesis reagent the enzyme may be reliably freed of deoxyribonuclease activity by an additional chromatographic procedure using a commercially avialable resin.
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PMID:The purification of nuclease-free T4-RNA ligase. 21 95

We have previously shown that the carboxyl-terminal tryptic peptide of the tumor suppressor p53 coeluted from reverse-phase high-performance liquid chromatography (HPLC) with ribonucleotides, suggesting the possible linkage of RNA to p53. In this report, we establish that p53 is covalently linked to RNA, using biochemical criteria at the levels of both tryptic peptide and intact protein: the electrophoretic properties of a tryptic peptide containing phosphorylated Ser-389 and the HPLC chromatographic properties of p53 depend on the linked RNA, p53, purified through urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and HPLC, copurifies with RNA, and Ser-389 liberates ribonucleotides upon RNase or alkali treatment. Wild-type and mutant p53s from both simian virus 40 (SV40)-transformed and SV40-nontransformed cells are RNA linked, indicating that RNA linkage may be a general property of p53. The RNA is labeled in vivo with 3H-uridine and in vitro by RNA ligase, suggesting that the RNA is bound by a 5' linkage. The RNA is a long-lived, integral component of p53 rather than a transient reaction intermediate. RNA linkage occurs at an evolutionarily conserved site on p53. We propose that RNA-linked p53 is a major biologically active form of p53 and that its interaction with RNA-linked SV40 T antigen reflects a role in RNA metabolism.
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PMID:The tumor suppressor p53 is bound to RNA by a stable covalent linkage. 170 9

We identified a Mg2+ dependent 5' exo-ribonuclease and an RNA ligase in cell-free extracts of Trypanosome brucei. The exo-ribonuclease in S100 or nuclear extracts, removes about 20 nts from the 5' end of SP6 derived capped as well as uncapped RNA and then stops. In contrast to the activity of the exo-ribonuclease on capped SP6 mini-exon transcripts, the exonuclease cannot degrade trypanosome-derived mini-exon transcripts or the mini-exon located at hsp 70 mRNAs. We therefore assume that the four secondary base modifications adjacent to the mini-exon cap, generated in vivo, confer resistance to the exo-ribonuclease. After exonuclease shortening of SP6 transcripts, an RNA ligase catalizes intramolecular ligation, generating a 3'-5' phosphodiester bond in a Mg2+ and ATP dependent reaction.
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PMID:A 5' exo-ribonuclease and RNA ligase of T. brucei. 246 Aug 26

The nucleotide sequence of the two major Drosophila melanogaster tRNATyr isoacceptors was determined to be pC-C-U-U-C-G-A-U-A-m2G-C-U-C-A-G-D-D-G-G-acp3 U-A-G-A-G-C-m2(2)G-G-psi-G-G-A-C-U-G/Q-psi-A-m1G-A-Um-C-C-A-U-A-G-m7 G-D-C-G-C-U-G-G-U(T)-psi-C-A-m1A-A-U-C-C-G-G-C-U-C-G-A-A-G-G-A-A-C-C-AOH . The two isoacceptors differ by the presence of a G or a Q in the wobble position. Both contain a partial modification in position 54 (U/T). Thus, these tRNAs are transcribed from a single gene (or many genes with identical sequences). A fast and sensitive postlabeling method for sequencing tRNA anticodons is described. Nuclease S-1-treated tRNA is labeled with 5[32P]-pCp using T-4 RNA ligase. The tRNA fragments are then separated on 7 M urea/20% PAA gels. After autoradiography the RNA is eluted and digested with T-2 RNase. The nature of the labeled nucleotides is determined by two-dimensional thin-layer chromatography. The same method can be used to determine the 5' sequence of a tRNA by 3' labeling 5' tRNA halves with 5[32P]-pCp and subsequent chemical sequencing.
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PMID:The nucleotide sequence of two homogeneic Drosophila melanogaster tRNATyr isoacceptors: application of a rapid tRNA anticodon sequencing method using S-1 nuclease. 301 Aug 77

The binding sites for influenza viral RNA polymerase on genome RNA segments were investigated. Ribonucleoprotein (RNP) cores containing the RNA polymerase were isolated from detergent-treated virions by glycerol gradient centrifugation. On ApG-primed in vitro transcription by the isolated RNP cores, different levels of RNA transcripts were synthesized for the eight RNP cores, suggesting an uneven distribution of the RNA polymerase. 3'-Terminal labeling of the RNP cores with the use of [32P]pCp and T4-RNA ligase indicated a reciprocal correlation between the levels of the RNA-3' label and RNA synthesis. Centrifugation of detergent-treated virions in a double gradient of cesium trifluoroacetate (or cesium chloride) and glycerol yielded RNA polymerase-RNA complexes devoid of NP, the major RNA-bound protein, but the pattern of RNA-3' labeling remained virtually unaffected. All these observations together indicated that the RNA polymerase is associated near the 3' termini of some viral RNA segments, thereby preventing the in vitro labeling of the RNA-3' ends. The results of foot-printing experiments using RNase V1 and RNase T2 were in agreement with this model.
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PMID:Identification of the RNA polymerase-binding site on genome RNA of influenza virus. 343 66

Behaviour of modified nucleosides, tRNA components, and their analogues has been studied in the internucleotide bond formation catalysed by ribonucleases of various substrate specificity, polynucleotide phosphorylases, and T4 RNA ligase and the results are summarised in this paper. Pseudouridine, dihydrouridine, ribothymidine, 5-methylcytidine, inosine, and 6-methyladenosine can participate in the reaction of internucleotide bond formation the presence of most ribonucleases used, viz. Pb2, Pcl2, Pb1, Pch1, C2, T1, pancreatic RNase. 3-Methylcytidine and 4-acetylcytidine form internucleotide bond (as phosphate acceptors) usually by means of guanyl-specific ribonucleases, whereas 1-methylandenosine is incorporated with ribonuclease Pel2. 7-Methylguanosine and 1-methylguynosine 2',3'-cyclophosphates can be used as phosphate donors in the presence of ribonuclease Pb2; in the similar enzymatic reaction 6-isopentenyladenosine is an uneffective acceptor.
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PMID:[Enzymatic incorporation into oligonucleotides of modified nucleosides]. 367 47

A 125-kilodalton (kDa) phosphoprotein was isolated from nucleoli of Novikoff hepatoma cells in the presence of various inhibitors of proteases, alkaline phosphatase, and RNase. This protein was the most highly phosphorylated protein found thus far in the nucleolus. The half-life of [32P]phosphate in the 125-kDa phosphoprotein was approximately 60 min. Amino acid analysis of the protein showed it had a high serine content (15.5 mol %), a high glutamine plus glutamic acid content (15.5 mol %), and a high lysine content (10.3 mol %). Phosphoserine was the only phosphorylated amino acid identified. After alkaline hydrolysis of the 32P-labeled protein, ribonucleotides were found which accounted for approximately 8.5% of the [32P]phosphate. After cytidine 3',5'-[32P]diphosphate ([32P]pCp) labeling by RNA ligase, several oligoribonucleotide sequences were purified including GGGCOH and GGGGCOH. The binding of oligonucleotides to peptides was stable under denaturing fractionation conditions including 6 M urea treatment and incubation at 100 degrees C for 10 min in sodium dodecyl sulfate and beta-mercaptoethanol. Furthermore, when nucleotide-peptide complex was treated with ribonuclease T2 followed by snake venom phosphodiesterase, the junctional nucleotide pCp was released. These results suggest that one or more ribonucleotides are covalently bound to the 125-kDa phosphoprotein.
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PMID:Isolation and characterization of a 125-kilodalton rapidly labeled nucleolar phosphoprotein. 408 83

The 3' terminus of the strand (minus strand) complementary to poliovirion RNA (plus strand) has been examined to see whether this sequence extends to the 5'-nucleotide terminus of the plus strand, or whether minus-strand synthesis terminates prematurely, perhaps due to the presence of a nonreplicated nucleotide primer for initiation of plus-strand synthesis. The 3' terminus was labeled with 32P using [5'-32P]pCp and RNA ligase, and complete RNase digests were performed with RNases A, T1, and U2. 32P-oligonucleotides were analyzed for size by polyacrylamide-urea gel electrophoresis. The major oligonucleotide products formed were consistent with the minus strand containing 3' ends complementary and flush with the 5' end of the plus strand. However, a variable proportion of the isolated minus strands from different preparations were heterogeneous in length and appeared to differ from each other by the presence of one, two, or three 3'-terminal A residues.
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PMID:Heterogeneity of the 3' end of minus-strand RNA in the poliovirus replicative form. 625 64

A combination of several enzymes, RNase-T1, nuclease S1, T4-polynucleotide kinase and T4-RNA ligase were used to prepare and modify different fragments of yeast tRNAAsp (normal anticodon G U C). This allowed us to reconstitute, in vitro, a chimeric tRNA that has any of the four bases G, A, U or C, as the first anticodon nucleotide, labelled with (32p) in its 3' position. Such reconstituted (32p) labelled yeast tRNAAsp were microinjected into the cytoplasm or the nucleus of the frog oocyte and checked for their stability as well as for their potential to work as a substrate for the maturation (modifying) enzymes under in vivo conditions. Our results indicate that the chimeric yeast tRNAsAsp were quite stable inside the frog oocyte. Also, the G34 was effectively transformed inside the cytoplasm of frog oocyte into Q34 and mannosyl-Q34; U34 into mcm5s2U and mcm5U. In contrast, C34 and A34 were not transformed at all neither in the cytoplasm nor in the nucleus of the frog oocyte. The above procedure constitutes a new approach in order to detect the presence of a given modifying enzyme inside the frog oocyte; also it provides informations about its cellular location and possibility about its specificity of interaction with foreign tRNA.
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PMID:Enzymatic replacement in vitro of the first anticodon base of yeast tRNAAsp: application to the study of tRNA maturation in vivo, after microinjection into frog oocytes. 628 19


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