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:3.1.26.5 (RNase P)
1,348 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nucleotide sequence of Escherichia coli DNA at both ends of the gene for 16S rRNA has been determined for two rRNA operons, rrnD and rrnX. The 400 nucleotides we have examined exhibit only one base change between rrnD and rrnX. Within the 160 nucleotides that precede mature 16S rRNA sequences are cleavage sites for several E. coli endonucleases, including RNase III. A 240-nucleotide segment encompassing the 16S 3' end contains another RNase III site and the point of presumed RNase P scission at the 5' end of tRNA1Ile, the first tRNA appearing in the 16-23S spacer region of rrnD and rrnX. Most importantly, the DNA sequences predict that regions flanking the 16S gene in the rRNA primary transcript extensively base pair to form a double-helical structure whose hairpin loop includes the entire mature 16S molecule; within this structure is a 26-base-pair stem containing the two sequences at which RNase III action generates the 5' and 3' ends of a previously characterized precursor to 16S rRNA. Although our proposed secondary structure for this RNase III site is superficially dissimilar to previously described cleavage sites in the T7 early mRNA precursor, certain common features may constitute signals for RNase III recognition. The suggestion that distant portions of an RNA molecule can form a secondary structure within which specific endonucleolytic cleavages occur may have mechanistic implications for the joining of noncontiguous portions of gene sequences evident in several eukaryotic mRNAs.
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PMID:Complementary sequences 1700 nucleotides apart form a ribonuclease III cleavage site in Escherichia coli ribosomal precursor RNA. 35 89

The transducing phages lambdadaroE and lambdadilv5, which carry the Escherichia coli ribosomal RNA operons rrnD and rrnX, respectively, have been mapped with the restriction endonucleases BamHI, EcoRI, HindIII, and Sma I. Using hybridization techniques, we have located the ribosomal RNA genes on these phage DNAs. The DNA sequence of the 437-base-pair 16 S-23 S ribosomal RNA intergenic spacer in the two rRNA operons rrnD and rrnX has been determined. The nucleotides examined exhibit only one base pair change between rrnD and rrnX. Both spacer regions contain the genes for tRNA1Ile and tRNA1BAla; the gene sequences are identical with the previously deduced tRNA sequences and are clustered within the first 60% of the spacer DNA. The most striking feature of the 16 S-23 S intergenic region in these two operons is the disparity in G-C content between the tRNA gene sequences (60% G-C) and the remaining spacer DNA (37% G-C). Spacer sequences are known to be involved in the processing of the ribosomal RNA transcript by RNase III and RNase P. In addition, we report the sequence of the first 108 base pairs of the 23 S rRNA gene.
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PMID:Sequence of the 16 S-23 s spacer region in two ribosomal RNA operons of Escherichia coli. 37 88

1. A precursor to small stable RNA, 10Sa RNA, accumulates in large amounts in a temperature sensitive RNase E mutant at non-permissive temperatures, and somewhat in an rnc (RNase III-) mutant, but not in an RNase P- mutant (rnp) or wild type E. coli cells. 2. Since p10Sa RNA was not processed by purified RNase E and III in customary assay conditions, we purified p10Sa RNA processing activity about 700-fold from wild type E. coli cells. 3. Processing of p10Sa RNA by this enzyme shows an absolute requirement for a divalent cation with a strong preference for Mn2+ over Mg2+. Other divalent cations could not replace Mn2+. 4. Monovalent cations (NH+4, Na+, K+) at a concentration of 20 mM stimulated the processing of p10Sa RNA and a temperature of 37 degrees C and pH range of 6.8-8.2 were found to be optimal. 5. The enzyme retained half of its p10Sa RNA processing activity after 30 min incubation at 50 degrees C. 6. Further characterization of this activity indicated that it is RNase III. 7. To further confirm that the p10Sa RNA processing activity is RNase III, we overexpressed the RNase III gene in an E. coli cells that lacks RNase III activity (rnc mutant) and RNase III was purified using one affinity column, agarose.poly(I).poly(C). 8. This RNase III preparation processed p10Sa RNA in a similar way as observed using the p10Sa RNA processing activity purified from wild type E. coli cells, confirming that the first step of p10Sa RNA processing is carried out by RNase III.
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PMID:Characterization of the RNA processing enzyme RNase III from wild type and overexpressing Escherichia coli cells in processing natural RNA substrates. 137 63

We recently showed that RNase III can process a small stable RNA, precursor 10Sa RNA, that accumulates in an rne (RNase E) strain at non-permissive temperatures. Precursor 10Sa (p10Sa) RNA is processed to 10Sa RNA in two steps, the first step is catalyzed by RNase III in the presence of Mn2+ but not Mg2+. It was shown that RNase III cosediments with membrane preparation from wild type as well as RNase III overexpressing cells. However, the possibility of membrane preparation contamination with ribosomes could not be ruled out. Here we show that RNase III, E and P are not associated with ribosomes. E. coli cells were opened either by alumina grinding or by sonication and fractionated into cytosolic and pellet fractions. The characterization of membrane preparations was done by assaying NADH oxidase, a bona fide membrane enzyme. Ribosomes prepared by alumina grinding were found to be contaminated with small fragments of membrane which contained RNase III activity. RNase III and NADH oxidase activities were present in the ribosomal preparations which could be solubilized by reagents that dissolve the inner membrane. Isopycnic sucrose gradient centrifugation of the membrane and ribosomal preparations also confirmed that RNase III fractionated with the inner membrane. Similarly RNase P activity was found in the corresponding fractions when isopycnic centrifugation of membrane and ribosome preparations was carried out. RNase E activity was also found to be present mostly in the post-ribosomal supernatant. These findings show that RNase III, E and P are not ribosomal enzymes.
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PMID:RNA processing enzymes RNase III, E and P in Escherichia coli are not ribosomal enzymes. 172 76

Cells overexpressing the RNA-processing enzymes RNase III, RNase E and RNase P were fractionated into membrane and cytoplasm. The RNA-processing enzymes were associated with the membrane fraction. The membrane was further separated to inner and outer membrane and the three RNA-processing enzymes were found in the inner membrane fraction. By assaying for these enzymatic activities we showed that even in a normal wild-type strain of Escherichia coli these enzymes fractionate primarily with the membrane. The RNA part of RNase P is found in the cytosolic fraction of cells overexpressing this RNA, while the overexpressed RNase P protein sediments with the membrane fraction; this suggests that the RNase P protein anchors the RNA catalytic moiety of the enzyme to a larger entity. The implications of these findings for the cellular organization of the RNA-processing enzymes in the cell are discussed.
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PMID:Location of the RNA-processing enzymes RNase III, RNase E and RNase P in the Escherichia coli cell. 194 11

The splice junction sequence of td mRNA from T4-infected cells has been determined (5'....GGU-CUA....3') and shown to be identical to that of the RNA ligation product encoded by the cloned gene [Belfort et al. Cell 41 (1985) 375-382]. The RNA processing functions, T4 RNA ligase, T4 polynucleotide kinase, and the host prr gene product appear not to be essential for exon ligation; neither are the host endoribonucleases RNase III, RNase P and RNase E required for intron excision. While these results are consistent with the autocatalytic splicing mechanism demonstrated in vitro [Chu et al. J. Biol. Chem. 260 (1985) 10680-10688], they leave unanswered the question of which protein(s), if any, might stimulate the in vivo reaction. Analysis of the products of the cloned td gene has led to identification of two td-encoded polypeptides, namely a polypeptide corresponding to the exon-I-coding sequence (NH2-TS), and the catalytically active thymidylate synthase (TS). Kinetic and nucleotide sequence data provide evidence that NH2-TS is the product of the primary transcript and that TS is encoded by spliced mRNA. These results suggest that splicing may provide a switch controlling the relative expression of NH2-TS and TS, two proteins with markedly different temporal appearances despite their identical transcriptional and translational start sites.
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PMID:RNA splicing and in vivo expression of the intron-containing td gene of bacteriophage T4. 242 90

The bla and ompA gene transcripts were used as substrates to probe Escherichia coli extracts for ribonucleolytic activities. A site specific endoribonucleolytic activity was identified that cleaves ompA and bla mRNA. The cleavages occur in vitro and in vivo. For both the bla and ompA mRNA most of the cleavage sites which were identified map in the 5' non-coding region. The cleavages of the ompA transcript have been previously suggested to regulate the growth rate dependent stability of this mRNA. Thus we propose that the identified endoribonucleolytic activity may be involved in the degradation of mRNA. Analysis of mutants revealed that the cleavages are mediated by endonucleases which do not seem to be identical to RNase III, RNase E or RNase P.
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PMID:In vivo and in vitro identity of site specific cleavages in the 5' non-coding region of ompA and bla mRNA in Escherichia coli. 304 39

RNase III cleaves precursor 16S RNA and precursor 23S RNA from the ribosomal RNA transcript. In vitro transcription experiments, using plasmids with the rrnB operon truncated in the 16S RNA and with various deletions in the spacer tRNA region, showed that no matter what size of deletion if the tRNA gene was affected RNase III processing of 16S RNA became incomplete. In comparison to a control plasmid, where only the 16S RNA gene was truncated and that showed normal RNA processing, plasmids where the tRNA gene was deleted partially or totally either the 5' or the 3' end of 16S RNA was processed. This relation between RNase III processing and the 3-dimensional structure of tRNA suggests an interaction between RNase III and a tRNA processing enzyme most probably RNase P.
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PMID:The tRNAGlu2 gene in the rrnB operon of E. coli is a prerequisite for correct RNase III processing in vitro. 304 74

Stability of RNA was tested in strains of Escherichia coli carrying single, double, or triple mutations in the RNA processing enzymes RNase III, RNase E and RNase P. Tests were carried out for total pulse labeled RNA, beta-galactosidase mRNA and for the decay of preexisting RNA during carbon starvation. Decay of RNA was measured at permissive and nonpermissive temperatures, and in no case were significant differences between mutants and non-mutant strains found. Therefore, we conclude that the three processing enzymes; RNase III, E and P do not contribute significantly to turnover of RNA IN Escherichia coli.
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PMID:Decay of RNA in RNA processing mutants of Escherichia coli. 615 28

A precursor molecule for 10Sb (M1) RNA, the RNA moiety of the RNA processing enzyme ribonuclease P (EC 3.1.26.5), is accumulated transiently in an Escherichia coli strain containing a plasmid that carries the 10Sb RNA gene. The same RNA precursor molecule is accumulated, in relatively large quantities, in a temperature-sensitive RNase E- mutant at the nonpermissive temperature. The RNA precursor includes 10Sb RNA and an extra 3' fragment that contains a termination stem and loop. It can be processed in vitro to a molecule the size of 10Sb RNA. None of the four endoribonucleases of E. coli--RNase III, RNase E, RNase F, or RNase P--takes part in this cleavage reaction. Therefore, we suggest that the processing of the precursor-10Sb RNA to 10Sb RNA is carried out by a thus-far unidentified endoribonuclease. The accumulation of a RNA molecule in a RNase E- mutant that does not contain a cleavage site for RNase E has been encountered previously and can be explained by assuming the existence of a RNA processing complex in the E. coli cell.
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PMID:Identification of a precursor molecular for the RNA moiety of the processing enzyme RNase P. 619 33


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