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:3.1.26.3 (RNase III)
1,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have isolated overlapping RNA fragments which contain the region surrounding the ribonuclease III cleavage site between bacteriophage T7 genes 0.3 and 0.7. Although all of these fragments contain the site of cleavage, only certain fragments are correctly recognized and cleaved by RNase III. Analysis of the cleavage products of the fragments indicates that the enzyme produces a single endonucleolytic break at this site in the T7 early RNA precursor molecule. In addition, the 3'-terminal adenylic acid residues observed previously on the in vivo T7 early RNA species were not found in these fragments and, therefore, must represent a post-transcriptional, post-processing modification of the RNA.
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PMID:The isolation and characterization of bacteriophage T7 messenger RNA fragments containing an RNase III cleavage site. 99 37

We reported earlier that the addition of double-stranded RNA and ATP increases the endonuclease activity more in an extract of Ehrlich ascites tumor cells which have been treated with an interferon preparation than in a comparable extract from control cells. We report here that the addition of double-stranded RNA to an extract from Ehrlich ascites tumor cells which have been treated with an interferon preparation [or with the interferon inducer poly(I)-poly(C)] promotes the phosphorylation by [gamma-32P]ATP of at least two proteins: P1 (molecular weight of 64,000) and P2 (molecular weight of 37,000). Double-stranded RNA also promotes the phosphorylation of at least one (i.e., P1) of these two proteins in an extract from cells which have not been treated with interferon, but the extent of phosphorylation is much smaller. Double-stranded RNA which has been degraded by RNase III, or DNA, does not promote the phosphorylation.
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PMID:Interferon, double-stranded RNA, and protein phosphorylation. 106 6

We have evaluated three methods which respond specifically to stable RNA-RNA duplexes and have compared their utility for examining several sorts of nucleic acids. We find that these methods, stepwise chromatography on Whatman CF11-cellulose; digestion with Escherichia coli RNase III; and specific inhibition of globin synthesis in vitro in rabbit reticulocyte lysates, are able to distinguish between stable double-stranded RNA and single-stranded RNA in the expected manner. The most sensitive method, inhibition of globin synthesis, responds to double-stranded RNA concentrations below 0.1 ng per ml. We have used the predominantly single-stranded RNA from several RNA bacteriophages of E. coli to test both the sensitivity and selectivity of these methods. The three viral RNAs tested contain low levels of double-stranded RNA which can be readily removed, leaving RNA which is not recognized as double-stranded RNA, despite indications from physical and sequencing studies that secondary structure is present. In particular, a potential hairpir loop of known sequence has been isolated from phage f2 RNA. Its properties were found to depart significantly from those of RNA-RNA duplexes by those two of our three methods capable of testing RNA of this size. Analysis of two eukaryotic mRNA populations by these methods was complicated by the presence of poly(A). Synthetic poly(A) chromatographs like double-stranded RNA on cellulose CF11 columns, and we could distinguish it from reovirus double-stranded RNA only at elevated temperatures.
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PMID:Sensitive methods for the detection and characterization of double helical ribonucleic acid. 108 42

Ribonuclease III-deficient strains of Escherichia coli accumulate a "30 S" RNA species. Kinetic analysis of label incorporated into rRNA species shows, however, that 30 S RNA is not the major precursor to the 16 S and 23 S RNA species is in 7- to 10-fold excess over that into 30 S RNA. The 30 S RNA species turns over with a half-life of about 2.5 min, which could account for no more than one-tenth of the incorporation into 16 S plus 23 S RNA. Thus, under these conditions RNase III-strains of E. coli do not cut rRNAs from an intact tandem precursor molecule but rather from the elongating nascent transcript, possibly by an alternate pathway not involving RNase III.
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PMID:Escherichia coli ribosomal ribonucleic acids are not cut from an intact precursor molecule. 109 Jun 20

We have studied the nuclease activities present in preparations of Escherichia coli RNase III and the "sizing factor" responsible for specific processing of several RNA species. RNase III preparations contain three activities: one which solubilizes stable RNA:RNA duplexes; one which solubilizes the RNA of DNA:RNA hybrids; and one which processes the polycistronic mRNA of bacteriophage T7 in a manner identical with sizing factor. We show that the activity against the RNA of DNA:RNA hybrids can be removed, but that the activity which cleaves RNA:RNA duplexes and that responsible for specific processing of phage T7 polycistronic mRNA appear to be identical by several biochemical criteria. In addition, partially purified enzyme fractions from mutants lacking these two activities contain substantial amounts of activity against the RNA of DNA:RNA hybrids. We have also defined several properties of the two activities solubilize RNA:RNA duplexes and RNA of DNA:RNA hybrids. Average oligonucleotide chain length in an exhaustive digest of double-stranded RNA is about 15 bases, while that in a digest of the RNA in DNA:RNA hybrids is less than 10 bases. Direct analysis shows that both activities cleave RNA chains to yield 5'-phosphate and 3'-hydroxyl termini. All four bases can reside at the 5' end of the resulting oligonucleotides, although both activities show a mild preference for certain bases. These results and previous findings allow us to specify the probably size and structure of potential cleavage sites for these enzymes in biological RNA molecules.
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PMID:Ribonucleic acid processing activity of Escherichia coli ribonuclease III. 109 44

A ribonucleoprotein particle (46S) has been isolated from [3H]uridine pulse-labeled cultures of E. Coli AB301/105. Evidence from pulse chase experiments and from protein analysis suggested that this particle may give rise to both the 30S and 50S ribosomal subunits. Direct deproteinization of the particle yielded 30S RNA, while deproteinization after treatment with a crude RNase III preparation yielded products similar to 23S and 16S RNA. This result is consistent with the idea that the 46S ribonucleoprotein is the in vivo counterpart of 30S RNA, which is the in vitro product obtained after phenol extraction.
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PMID:A ribonucleoprotein precursor of both the 30S and 50S ribosomal sunbunits of Escherichia coli. 109 84

The 30 S ribosomal precursor RNA has been prepared from Escherichia coli AB301/105 (RNase III-) labeled with 32-PO4 in the presence of chloramphenicol. Direct nucleotide sequence studies yield the following information. 1. The major 5'-terminal sequence in our precursor preparations is pppA-C-U-G-. 2. Treatment of the precursor RNA with purified ribonuclease III in vitro releases species sedimenting near 23 S and 17 S, neither of which retain the pppA- end, plus a collection of small fragments with chain lengths of less than 400 nucleotides. 3. The RNase III product sedimenting near 17 S (16 SIII) appears identical with the 17 S RNA typically isolated from pulse-labeled or chloramphenicol-treated cells or from several mutants deficient in ribosome assembly: fingerprint analysis reveals the presence of the same additional RNase T1 oligonucleotides and the 5' terminus (pU-G-) previously described for 17 S RNA. A 3'-terminal T1 oligonucleotide (which was not previously identifiable in the case of the 17 S precursor) has been isolated from 16 S III and its sequence determined: C-U-C-A-C-A-C-A. 4. 5 S rRNA sequences are contained in an RNase III-released fragment of approximately 300 nucleotides. This molecule lacks the 5' terminus of the mature 5 S RNA. The implications of these findings with respect to the control of ribosomal RNA synthesis, the pathways of rRNA processing in vivo, and the specificity of RNase III cleavage of natural substrates are discussed.
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PMID:The 30 S ribosomal precursor RNA from Escherichia coli. A primary transcript containing 23 S, 16 S, and 5 S sequences. 109 85

the mutation that causes ribonuclease III (RNase III) deficiency in strain AB301-105 of Kindler et al. (1973) has been mapped by use of F' merodiploids, Hfr matings, and P1 transduction. This mutation, rnc-105, lies close to nadB, near 49 min on the genetic map of Escherichia coli. The rnc-105 mutation has been transferred from its original genetic background by transduction and conjugation, and these new strains have the same defects in ribonucleic acid processing reported previously for AB301-105. Strains that carry rnc-105 grow more slowly than parental rnc+ strains, but the difference in growth rate seems to depend on the genetic background of each strain. Bacteriophage T7 grows about equally well in RNase III+ and III- female strains of E. coli, even though the specific cuts that RNase III makes in T7 ribonucleic acid are not made in the RNase III- strains. A low-phosphate defined medium in which most E. coli strains seem to grow well was developed. This medium is equally useful for labeling ribonucleic acids with 32PO4 and as a selective medium for genetic manipulations. It was used to determine the growth requirements of strain AB301-105, which are biotin and succinate in addition to the methionine and histidine requirements of the parental strain. The biotin mutation lies near the position expected from known mutations of E. coli, but the succinate mutation apparently does not. The possibility that the succinate requirement could be due to the RNase III deficiency is discussed. A uraP mutation was isolated for use in transferring rnc-105 between strains by conjugation. It lies near 47 min, somewhat removed from the commonly accepted position for uraP.
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PMID:Genetic mapping of a mutation that causes ribonucleases III deficiency in Escherichia coli. 110 Jun 5

Localization of a mutation affecting ribonuclease III activity (an enzyme specific for double-stranded ribonucleic acid) in Escherichia coli was attempted. By a series of matings and transduction experiments, the mutation rnc-105 was mapped near the nadB gene. In strains carrying this mutation, another mutation (ranA2074) was also found. Based on available data, their order on the E. coli chromosome appears to be tyrA, ranA, nadB, rnc, purI. Strains carrying either the ranA2074 or the rnc-105 mutation fail to grow at 45 C in enriched medium, whereas strains carrying only the rnc-105 mutation are defective in ribonuclease III activity. Strains carrying either of these mutations grow more slowly than corresponding wild-type strains in all media tested at all temperatures; the rnc-105 mutation reduces the growth rate more than the ranA2074 mutation. T4 and T7 bacteriophages form plaques with a lower efficiency on strains carrying the rnc-105 mutation than on other strains. Thus we suggest that ribonuclease III is beneficial for normal growth of E. Coli and that at higher temperatures it becomes indispensable.
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PMID:Mapping and characterization of a mutation in Escherichia coli that reduces the level of ribonuclease III specific for double-stranded ribonucleic acid. 110 Jun 6

Escherichia coli ribonuclease III cleaves adenovirus messenger RNA and mammalian 28S and 18S ribosomal RNA. Fragmentation is not random, but in each case a specific collection of products is generated. This points to the potential use of the enzyme as a tool for specific fragmentation of RNA. Cleavage by RNase III abolishes the capability of adenovirus messenger RNA to direct cell-free synthesis of virus polypeptides.
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PMID:Cleavage of adenovirus messenger RNA and of 28S and 18S ribosomal RNA by RNase III. 110 39


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