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

---

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

In Pseudomonas aeruginosa, arginine catabolism via the arginine deiminase pathway depends on the anaerobically inducible arcDABC operon, whose expression is further modulated by mRNA processing. Fusion of the cloned arc operon to an external tac promoter did not alter the processing pattern in P. aeruginosa and allowed heterologous expression in Escherichia coli. Processing within a specific region of the arcD mRNA was similar in P. aeruginosa and in E. coli. In E. coli, a conditional temperature-sensitive (ts) mutation in the gene specifying RNase E prevented cleavage of the arc mRNA at the non-permissive temperature, whereas mutations in the genes encoding RNase III or RNase P had no effect. We therefore speculate that in P. aeruginosa, an RNase E-like enzyme exists which is involved in the specific processing of the arc mRNA.
...
PMID:Processing of the Pseudomonas arcDABC mRNA requires functional RNase E in Escherichia coli. 768 78

ColE1 DNA replication is initiated by RNA II and inhibited by RNA I. Control of the replication occurs through the interaction between RNA I and RNA II. Therefore, RNases involved in the metabolism of RNA I and RNA II are expected to play a key role in the control of the ColE1 plasmid replication. RNase H, RNase E, RNase III, RNase P, and polynucleotide phosphorylase carry out the many specific reactions of the RNA metabolism.
...
PMID:RNases in ColE1 DNA metabolism. 890 10

M1 RNA of 377 nucleotides, the catalytic subunit of Escherichia coli RNase P, is produced by a 3' processing reaction from precursor M1 RNA, a major transcript from the rnpB gene. We analyzed products and intermediates generated by the in vitro processing reaction using a 40% ammonium sulfate precipitate of the S30 fraction (ASP-40) and determined their involvement in the processing. From the results we proposed a model of two pathways for 3' processing of M1 RNA. In this model, one pathway (pathway I) involves +385/+386 intermediates and the other pathway (pathway II) does not. The position of the 3'-end of the precursor molecule determined the choice of the pathways. The precursor having the 3'-end of +413 was processed by both pathways while that having the +415 end was processed only by pathway II. The ASP-40 fraction generated processing products (termed +378/+379 RNA) containing one or two more nucleotides at the 3'-end than M1 RNA, regardless of which pathway was used. Therefore, both pathways require the final 3' trimming for complete processing. The endonucleolytic generation of +378/+379 RNA by pathway II was blocked by the rne-3071 mutation, suggesting that this step is carried out by RNase E.
...
PMID:In vitro analysis of processing at the 3'-end of precursors of M1 RNA, the catalytic subunit of Escherichia coli RNase P: multiple pathways and steps for the processing. 988 89

Conversion of tRNA precursors to their mature forms requires the action of both endo- and exoribonucleases. Although studies over many years identified the endoribonuclease, RNase P, and several exoribonucleases as the enzymes responsible for generating the mature 5' and 3' termini, respectively, of Escherichia coli tRNAs, relatively little is known about how tRNAs are separated from long multimeric or multifunction transcripts, or from long leader and trailer sequences. To examine this question, the tRNA products that accumulate in mutant strains devoid of multiple exoribonucleases plus one or several endoribonucleases were analyzed by northern analysis. We find that the multifunction tyrT transcript, which contains two tRNA(Tyr)1 sequences separated by a 209-nt spacer region plus a downstream mRNA, is cleaved at three sites in the spacer region by the endoribonuclease, RNase E. When both RNase E and RNase P are absent, a product containing both tRNAs accumulates. Two multimeric tRNA transcripts, those for tRNA Arg-His-Leu-Pro and tRNA Gly-Cys-Leu also require RNase E for maturation. For the former transcript, products with long 3' extensions on tRNA(Arg), tRNA(His), and tRNA(Pro), as well as the primary transcript, accumulate in the absence of RNase E. For the latter transcript, RNase E cleaves downstream of each tRNA. Little processing of either multimeric transcript occurs in the absence of both RNase E and RNase P. These data indicate that RNase E is a major contributor to the initial processing of E. coli tRNA transcripts, providing substrates for final maturation by RNase P and the 3' exoribonucleases. Based on this new information, a detailed model for tRNA maturation is proposed.
...
PMID:RNase E plays an essential role in the maturation of Escherichia coli tRNA precursors. 1187 63

The Escherichia coli endoribonucleases RNase E (Rne) and RNase G (Rng) have sequence similarity and broadly similar sequence specificity. Whereas the absence of Rne normally is lethal, we show here that E. coli bacteria that lack the rne gene can be made viable by overexpression of Rng. Rng-complemented cells accumulated precursors of 5S ribosomal RNA (rRNA) and the RNA component of RNase P (i.e. M1 RNA), indicating that normal processing of these Rne-cleaved RNAs was not restored by RNase G; additionally, neither 5S rRNA nor M1 RNA was generated from precursors by RNase G cleavage in vitro. Using DNA microarrays containing 4405 Escherichia coli open reading frames (ORFs), we identified mRNAs whose steady-state level was affected by Rne, Rng or the N-terminal catalytic domain of RNase E. Most transcript species affected by RNase E deficiency were also elevated in an rne deletion mutant complemented by Rng. However, approximately 100 mRNAs that accumulated in Rne-deficient cells were decreased by rng-complemention, thus identifying targets whose processing or degradation may be the basis for RNase E essentiality. Remarkably prominent in this group were mRNAs implicated in energy-generating pathways or in the synthesis or degradation of macromolecules.
...
PMID:RNase G complementation of rne null mutation identifies functional interrelationships with RNase E in Escherichia coli. 1195 97

RNase E, an essential endoribonuclease in Escherichia coli, is involved in 9S rRNA processing, the degradation of many mRNAs, and the processing of the M1 RNA subunit of RNase P. However, the reason that RNase E is required for cell viability is still not fully understood. In fact, recent experiments have suggested that defects in 9S rRNA processing and mRNA decay are not responsible for the lack of cell growth in RNase E mutants. By using several new rne alleles, we have confirmed these observations and have also ruled out that M1 processing by RNase E is required for cell viability. Rather, our data suggest that the critical in vivo role of RNase E is the initiation of tRNA maturation. Specifically, RNase E catalytic activity starts the processing of both polycistronic operons, such as glyW cysT leuZ, argX hisR leuT proM, and lysT valT lysW valZ lysY lysZ lysQ, as well as monocistronic transcripts like pheU, pheV, asnT, asnU, asnV, and asnW. Cleavage by RNase E within a few nucleotides of the mature 3' CCA terminus is required before RNase P and the various 3' --> 5' exonucleases can complete tRNA maturation. All 59 tRNAs tested involved RNase E processing, although some were cleaved more efficiently than others.
...
PMID:Initiation of tRNA maturation by RNase E is essential for cell viability in E. coli. 1200 Jul 93

Bacteriophage P4 immunity is controlled by a small stable RNA (CI RNA) that derives from the processing of primary transcripts. In previous works, we observed that the endonuclease RNase P is required for the maturation of CI RNA 5'-end; moreover, we found that polynucleotide phosphorylase (PNPase), a 3' to 5' RNA-degrading enzyme, is required for efficient 5'-end processing of CI RNA, suggesting that 3'-end degradation of the primary transcript might be involved in the production of proper RNase P substrates. Here, we demonstrate that another Escherichia coli nuclease, RNase E, would appear to be involved in this process. We found that transcripts of the P4 immunity region are modified by the post-transcriptional addition of short poly(A) tails and heteropolymeric tails with prevalence of A residues. Most oligoadenylated transcripts encompass the whole cI locus and are thus compatible as intermediates in the CI RNA maturation pathway. On the contrary, in a polynucleotide phosphorylase (PNPase)-defective host, adenylation occurred most frequently within cI, implying that such transcripts are targeted for degradation. We did not find polyadenylation in a pcnB mutant, suggesting that the pcnB-encoded polyadenyl polymerase I (PAP I) is the only enzyme responsible for modification of P4 immunity transcripts. Maturation of CI RNA 5'-end in such a mutant was impaired, further supporting the idea that processing of the 3'-end of primary transcripts is an important step for efficient maturation of CI RNA by RNase P.
...
PMID:RNase E and polyadenyl polymerase I are involved in maturation of CI RNA, the P4 phage immunity factor. 1205 40

M1 RNA, the catalytic component of Escherichia coli RNase P, is derived from the 3'-end processing of precursor M1 RNA, a major transcript of the rnpB gene. In this study, we investigated the mechanism of 3'-end processing of M1 RNA using the recombinant N-terminal half RNase E. The cleavage site preference of RNase E differed from that of the 40% ammonium sulfate precipitate (ASP-40), a partially purified cell extract containing processing activity. However, the addition of a trace amount of ASP-40 changed the cleavage site preference of RNase E to that of ASP-40 suggesting the involvement of a soluble factor in cleavage site preference.
...
PMID:3'-end processing of precursor M1 RNA by the N-terminal half of RNase E. 1237 5

Ribonuclease P (RNase P) is a ribonucleoprotein enzyme that catalyzes the 5' maturation of tRNA precursors. The bacterial RNase P holoenzyme is composed of a large, catalytic RNA and a small protein. Our previous work showed that Bacillus subtilis RNase P forms a specific "dimer" that contains two RNase P RNA and two RNase P protein subunits in the absence of substrate. We investigated the equilibrium and the structure of the dimeric and the monomeric holoenzyme in the absence and presence of substrates by synchrotron small-angle X-ray scattering, 3' autolytic processing, and hydroxyl radical protection. In the absence of substrate, the dimer-monomer equilibrium is sensitive to monovalent ions and the total holoenzyme concentration. At 0.1 M NH4Cl, formation of the dimer is strongly favored, whereas at 0.8 M NH4Cl, the holoenzyme is a monomer. Primary hydroxyl radical protection in the dimer is located in the specificity domain, or domain I, of the RNase P RNA. The ES complex with a substrate containing a single tRNA is always monomeric. In contrast, the dominant ES complex with a substrate containing two tRNAs is dimeric at 0.1 M NH4Cl and monomeric at 0.8 M NH4Cl. Our results show that the B. subtilis holoenzyme can be a dimer and a monomer, and the fraction of the dimer is very sensitive to the environment. Under a variety of conditions, both the holoenzyme dimer and monomer can be present in significant amounts. Because the majority of tRNA genes are organized in large operons and because of the lack of RNase E in B. subtilis, a dimeric holoenzyme may be necessary to facilitate the processing of large precursor tRNA transcripts. Alternatively, the presence of two forms of the RNase P holoenzyme may be required for other yet unknown functions.
...
PMID:Dimeric and monomeric Bacillus subtilis RNase P holoenzyme in the absence and presence of pre-tRNA substrates. 1239 25

Several tRNAs in the hyperthermophilic bacterium Aquifex aeolicus are encoded in clusters and as part of ribosomal RNA operons, implying the requirement for tRNA processing by ribonuclease P (RNase P). Intriguingly, neither a gene for the RNA nor the protein component of this ubiquitous ribonucleoprotein enzyme has been hitherto identified in the sequenced genome of A. aeolicus, despite extensive data mining. As a result of the present study, primer extension analysis revealed that tRNAs in A. aeolicus possess canonical mature 5' ends; yet we were unable to demonstrate RNase P holoenzyme or RNase P RNA alone activity in A. aeolicus extracts under a variety of reaction conditions utilizing mono- and dimeric ptRNA substrates. Processing of dimeric ptRNA transcripts in extracts of A. aeolicus disclosed at least one endoribonuclease which cleaves in the A/U-rich spacer of the tandem ptRNA, reminiscent of bacterial RNase E-like enzymes.
...
PMID:tRNA maturation in Aquifex aeolicus. 1245 59


<< Previous 1 2 3 Next >>

---