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)

We have employed S1 nuclease to probe the structure of an intermediate in tRNA biosynthesis available only in radiochemical purity. The dimeric precursor to tRNAGln and tRNALeu from bacteriophage T4 was digested with the single-strand specific nuclease, and the products of the reaction were compared with the S1 digestion products of the mature cognate tRNA'S. Quantitation and sequence analysis of the products revealed that the location and accessibility of S1 cleavage sites in the precursor were substantially identical with those in the mature forms. Based on these conclusions, it is argued that the dimer is comprised of two domains in which the specific features of both secondary and tertiary conformation closely resemble those found in the mature molecules; at the same time we noted small but apparently significant differences in certain regions of the molecule which may reflect signals for various maturation events. Finally, we have determined that the sites of precursor cleavage by RNase P, the endonuclease which generates the mature 5' termini of these tRNAs, were completely inaccessible to S1 digestion.
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PMID:S1 nuclease as a probe for the conformation of a dimeric tRNA precursor. 36 98

DNA sequences affecting the transcription of the Escherichia coli rnpB transcript encoding the catalytic M1 RNA subunit of RNase P have been analyzed. Previous work (Motamedi, H., Lee, Y., and Schmidt, F.J.) (1984) Proc. Natl. Acad. Sci. U. S. A. 81, 3959-3963) identified S1 nuclease protection products corresponding to transcripts originating upstream of the M1 RNA gene. Sequence analysis of the upstream region of rnpB identified three regions homologous to the E. coli consensus promoter sequence. In the present work, analysis of in vitro transcription products by S1 nuclease mapping indicated that all three promoter homologies were capable of directing transcription. The nearest promoter, P-1, was approximately 100 times more active than either of the upstream homologies P-2 and vivo experiments, wherein the three promoter homologies preceding rnpB were cloned into the galactokinase (GalK) expression vector pKO100. The promoter homology nearest to the M1 RNA gene directed the synthesis of GalK above background. The upstream promoter homologies did not direct the synthesis of GalK at a level greater than 1% of transcription from P-1. Deletion of the upstream homologies did not affect transcription from P-1. It was concluded that P-1 is responsible for essentially all M1 RNA transcription in vivo. Single-round transcription experiments in vitro detected strong NusA-independent transcriptional pausing at nucleotides +118 and +121 of the rnpB transcript, with a half-life of 27 s when concentrations of NTPs were near the average Km for elongation. Pausing at these points was eliminated by substitution of ITP for GTP in the transcription mixture. This suggests that pausing is dependent on transcript secondary structure. The position of pausing corresponds to that of a dual stem and loop structure of M1 RNA which has recently been proposed on the basis of phylogenetic sequence analysis.
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PMID:Sites of initiation and pausing in the Escherichia coli rnpB (M1 RNA) transcript. 246 43

The nucleotide sequence of a cloned gene for the RNA component of Escherichia coli ribonuclease P, M1 RNA, is presented. The sequence determined extends 320 nucleotides upstream of the 377-base-pair (bp) structural gene and includes three sequences homologous to the consensus E. coli promoter sequence. Two nucleotides found in the M1 RNA structural gene sequence were not found in a previously determined gene sequence of another M1 RNA clone [Reed, R. E., Baer, M. F., Guerrier-Takeda, C., Donis-Keller, H. & Altman, S. (1982) Cell 30, 627-636]. In vitro transcription of supercoiled plasmid DNA containing the M1 RNA gene resulted in a major transcript arising from the strong promoter nearest to the mature M1 RNA. RNAs encoded by the M1 RNA clone in vivo were examined by S1 nuclease mapping. The results indicated that in vivo transcripts originate from all three promoters preceding the M1 RNA gene. These transcripts are apparently processed in a multistep pathway to generate the 5' end of mature M1 RNA.
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PMID:Tandem promoters preceding the gene for the M1 RNA component of Escherichia coli ribonuclease P. 620 33

The polycistronic mRNA of the histidine operon is subject to a processing event that generates a rather stable transcript encompassing the five distal cistrons. The molecular mechanisms by which such a transcript is produced were investigated in Escherichia coli strains carrying mutations in several genes for exo- and endonucleases. The experimental approach made use of S1 nuclease protection assays on in vivo synthesized transcripts, site-directed mutagenesis and construction of chimeric plasmids, dissection of the processing reaction by RNA mobility retardation experiments, and in vitro RNA degradation assays with cellular extracts. We have found that processing requires (1) a functional endonuclease E; (2) target site(s) for this activity in the RNA region upstream of the 5' end of the processed transcript that can be substituted by another well-characterized rne-dependent cleavage site; (3) efficient translation initiation of the first cistron immediately downstream of the 5' end; and (4) a functional endonuclease P that seems to act on the processing products generated by ribonuclease E. This is the first evidence that ribonuclease P, an essential ribozyme required for the biosynthesis of tRNA, may also be involved in the segmental stabilization of a mRNA.
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PMID:Ribonuclease E provides substrates for ribonuclease P-dependent processing of a polycistronic mRNA. 800 21