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At least 145 records · Page 8Linked to original sources
PubMed1985

RNase-sensitive and RNase-insensitive protective components isolated from Listeria monocytogenes.

Crude ribosomes were isolated from Listeria monocytogenes serotype 4b and separated into two fractions by molecular sieve chromatography. Chemical analysis indicated that fraction I contained cell envelope components while fraction II contained the ribosomes. Both fractions protected mice against Listeria, but only in combination with the adjuvant dimethyldioctadecylammonium bromide (DDA). RNase-treatment, but not proteinase K-treatment destroyed the protective properties of fraction II, and RNA purified from fraction II also induced protection. Protection induced by fraction I was not affected by either RNase- or proteinase K-treatment. Both subcutaneous and intraperitoneal, but not intravenous administration of fraction I, fraction II, or purified RNA induced significant protection against intraperitoneal infection, the intraperitoneal route of administration being the most effective. All preparations induced high levels of protection 3 to 7 days after administration, but protection was already decreased after 14 days. Protection induced with RNA appeared to be biphasic, because it also protected mice 1 day, but not 2 days after administration. Protection induced with both fraction I and RNA was at least in part non-specific, because both preparations also protected mice against L. monocytogenes serotype 3, Streptococcus pneumoniae and Pseudomonas aeruginosa. Results are discussed in relation to previous work with analogous preparations from P. aeruginosa.

Animals↗
PubMed2001

A 'cassette' RNase: site-selective cleavage of RNA by RNase S equipped with RNA-recognition segment.

RNase S is a unique protein comprising the non-covalent association of two components, the S-peptide and the S-protein. An RNA-recognition segment derived from the human immunodeficiency virus (HIV)-1 Rev protein was conjugated with the S-peptide to form a complex with the S-protein. The resulting RNase S bearing the RNA-recognition segment preferentially hydrolyzed a single position of the RNA stem-loop derived from the specific binding site for the Rev protein.

Amino Acid Sequence↗
PubMed1993

mRNA processing independent of RNase III and RNase E in the expression of the F1845 fimbrial adhesin of Escherichia coli.

F1845, the fimbrial adhesin of a diarrhea-associated Escherichia coli, confers upon the bacteria the ability to adhere to cultured epithelial cells in a diffuse pattern. The fimbrial subunit gene, daaE, is encoded on a polycistronic mRNA which is processed endoribonucleolytically to produce a stable message encoding only daaE. The processing event occurs in bacterial strains with mutations in RNase III or RNase E, the only endoribonucleases which have been implicated in the processing of E. coli mRNA. Sequences encoding a stem-loop structure downstream of daaE play an essential role in determining the stability of the daaE mRNA. Rapid degradation of the sequences upstream of the cleavage site occurs upon processing, suggesting that processing of the F1845 polycistronic mRNA results in differential expression of genes involved in the biogenesis of fimbriae.

Adhesins, Escherichia coli↗
PubMed2001

The RNase P associated with HeLa cell mitochondria contains an essential RNA component identical in sequence to that of the nuclear RNase P.

The mitochondrion-associated RNase P activity (mtRNase P) was extensively purified from HeLa cells and shown to reside in particles with a sedimentation constant ( approximately 17S) very similar to that of the nuclear enzyme (nuRNase P). Furthermore, mtRNase P, like nuRNase P, was found to process a mitochondrial tRNA(Ser(UCN)) precursor [ptRNA(Ser(UCN))] at the correct site. Treatment with micrococcal nuclease of highly purified mtRNase P confirmed earlier observations indicating the presence of an essential RNA component. Furthermore, electrophoretic analysis of 3'-end-labeled nucleic acids extracted from the peak of glycerol gradient-fractionated mtRNase P revealed the presence of a 340-nucleotide RNA component, and the full-length cDNA of this RNA was found to be identical in sequence to the H1 RNA of nuRNase P. The proportions of the cellular H1 RNA recovered in the mitochondrial fractions from HeLa cells purified by different treatments were quantified by Northern blots, corrected on the basis of the yield in the same fractions of four mitochondrial nucleic acid markers, and shown to be 2 orders of magnitude higher than the proportions of contaminating nuclear U2 and U3 RNAs. In particular, these experiments revealed that a small fraction of the cell H1 RNA (of the order of 0.1 to 0.5%), calculated to correspond to approximately 33 to approximately 175 intact molecules per cell, is intrinsically associated with mitochondria and can be removed only by treatments which destroy the integrity of the organelles. In the same experiments, the use of a probe specific for the RNA component of RNase MRP showed the presence in mitochondria of 6 to 15 molecules of this RNA per cell. The available evidence indicates that the levels of mtRNase P detected in HeLa cells should be fully adequate to satisfy the mitochondrial tRNA synthesis requirements of these cells.

Biomarkers↗
PubMed2003

Genetic changes in the RNA components of RNase MRP and RNase P in Schmid metaphyseal chondrodysplasia.

BACKGROUND: The Schmid type of metaphyseal chondrodysplasia (MCDS) is generally due to mutations in COL10A1 encoding for type X collagen of cartilage. METHODS: We performed a study on the genes coding for the RNA components of RNase MRP (MRPR) and RNase P (H1RNA) among 20 patients with diagnosis of MCDS and no mutations in COL10A1. RESULTS: Two patients were found to be homozygous for a base substitution G for A at nucleotide 70 of RMRP, which is the major mutation causing cartilage-hair hypoplasia. No pathogenic mutations were detected in H1RNA. CONCLUSION: Cartilage-hair hypoplasia diagnosis should be considered in patients with metaphyseal chondrodysplasia even in the absence of any extra-skeletal manifestations if no mutation in COL10A1 can be found and the family history is compatible with autosomal recessive inheritance. Correct diagnosis is important for genetic counselling and for proper follow up of the patients.

Child, Preschool↗
PubMed2005

Enzymatic properties of serine 93 mutants of RNase Rh from Rhizopus niveus. A trial to alter the base preference of RNase Rh.

In order to investigate the effects of mutation of Ser93, a component of base recognition site (B2 site) of a base non-specific RNase from Rhizopus niveus, we prepared 10 mutant enzymes at this position, S93A, S93V, S93F, S93T, S93G, S93D, S93N, S93E, S93Q and S93R, and their enzymatic activities towards RNA and 16 dinucleoside phosphates were measured. Enzymatic activities of the mutant enzymes towards RNA were between 3.5-75% of the native enzyme. From the rates of hydrolysis of 16 dinucleoside phosphates by the mutant enzymes, we estimated the base preference of B1 and B2 base recognition sites. The results indicated that mutation of Ser93 to Phe, Thr, Glu. Gln and Arg caused the B2 site of the enzymes to more cytosine base preference and Asp and Asn substitution caused more uracil base preference. The results suggested that we are able to construct an enzyme that preferentially cleaves internucleotidic linkage at the 5'-side of cytidine or uridine. The results seem able to convert a base non-specific RNase to a base specific one.

Endoribonucleases↗
PubMed2006

Sequence analysis of RNase MRP RNA reveals its origination from eukaryotic RNase P RNA.

RNase MRP is a eukaryote-specific endoribonuclease that generates RNA primers for mitochondrial DNA replication and processes precursor rRNA. RNase P is a ubiquitous endoribonuclease that cleaves precursor tRNA transcripts to produce their mature 5' termini. We found extensive sequence homology of catalytic domains and specificity domains between their RNA subunits in many organisms. In Candida glabrata, the internal loop of helix P3 is 100% conserved between MRP and P RNAs. The helix P8 of MRP RNA from microsporidia Encephalitozoon cuniculi is identical to that of P RNA. Sequence homology can be widely spread over the whole molecule of MRP RNA and P RNA, such as those from Dictyostelium discoideum. These conserved nucleotides between the MRP and P RNAs strongly support the hypothesis that the MRP RNA is derived from the P RNA molecule in early eukaryote evolution.

Base Sequence↗
PubMed2003

Enzymatic properties of glutamine 32 mutants of RNase Rh from Rhizopus niveus, a trial to alter the most preferential inter-nucleotidic linkages of RNase Rh.

In order to investigate the effects of mutation of Gln32, a component of a base recognition site (B2 site) of a base-nonspecific RNase from Rhizopus niveus, we prepared several enzymes mutant at this position, Q32F, Q32L, Q32V, Q32T, Q32D, Q32N, and Q32E, and their enymatic activities toward RNA and 16 dinucleoside phosphates were measured. Enzymatic activities of the mutant enzymes towards RNA were between 10-125% of the native enzyme. From the rates of hydrolysis of 16 dinucleoside phosphates by mutant enzymes, we estimated the base specificity of both B1 and B2 sites. The results indicated that mutation of Gln32 to Asp, Asn, and Glu caused the B2 site to prefer cytosine more and to a less extent, to prefer uracil (Q32N), and that Q32F made the enzyme more guanine-base preferential. The results suggested that we are able to construct an enzyme that preferentially cleaves internucleotidic linkages, at the 5'-side of cytosine residues (Q32D, Q32N, and Q32E) and guanine residues (Q32F and Q32T), thus, cleaves purine-C(Q32D, Q32N, Q32E) and GpG and ApG (Q32F, and Q32T) most easily. The results seemed to suggest converting a base-non-specific RNase to a base-specific one.

Base Sequence↗
PubMed1993

Plant mitochondrial RNase P and E. coli RNase P have different substrate specificities.

Substrate specificity requirements of the plant mitochondrial RNase P were investigated with different natural and mutated substrates. Heterologous precursors with intact tRNAs from plant and fungal mitochondria, from bacteria, archaebacteria and of eukaryotic origins were processed faithfully, albeit with different efficiencies. Alteration of the acceptor stem length did not disturb correct processing, while activity is completely inhibited by deletion of the pseudouridine loop. Such and other minimal substrates processed by the E. coli RNase P are not recognized as substrates by the plant mitochondrial enzyme, suggesting different requirements for substrate recognition.

Culture Techniques↗
PubMed1997

A novel protein shared by RNase MRP and RNase P.

We have isolated suppressors of the temperature-sensitive rRNA processing mutation rrp2-2 in Saccharomyces cerevisiae. A class of extragenic suppressors was mapped to the YBR257w reading frame in the right arm of Chromosome II. Characterization of this gene, renamed POP4, shows that the gene product is necessary both for normal 5.8S rRNA processing and for processing of tRNA. Immunoprecipitation studies indicate that Pop4p is associated with both RNase MRP and RNase P. The protein is also required for accumulation of RNA from each of the two ribonucleoprotein particles.

Amino Acid Sequence↗
PubMed1999

Cleavage of double-stranded copy RNA by RNase 1 and RNase T1 provides a robust means to detect p53 gene mutations in clinical specimens.

Detecting somatic mutations in patient specimens is challenging because of the wide variation in quality and quantity of genomic DNA in clinically derived material. In cancer specimens, the challenge of detecting mutations is usually compounded by the presence of large numbers of nonmutated normal cells that dampen the relative signal that can be obtained from employing any mutation detection strategy. In the case of somatic mutations in the gene encoding the tumor suppressor, p53, a clinically useful mutation detection assay must be able to detect a wide variety of types of mutations scattered over five coding exons and their flanking intron sequences. This study examined the ability of a mutation detection strategy, termed NIRCA, to identify single-base mutations in the clinically relevant domain of the p53 gene. This strategy relies on RNase digestion-mediated cleavage of double-stranded copy RNA transcribed in vitro from polymerase chain reaction (PCR)-amplified genomic templates to detect mismatched base pairs resulting from hybridization of complimenting mutant and wild-type copy RNA strands. This assay system was found to robustly detect all twelve possible mismatches and the plus one and minus one frame shifts. Furthermore, the assay could detect mutations in clinical specimens when the mutant alleles composed as few as 4% of the total population of alleles isolated in bulk specimen genomic DNA. This mutation detection strategy worked efficiently in bladder, breast, colon and lung tumors as well as sediments from bladder cytology specimens.

Humans↗
PubMed1997

A bidirectional promoter connects the p14.5 gene to the gene for RNase P and RNase MRP protein subunit hPOP1.

We have identified the functional promoter of the translational inhibitor p14.5, the human homologue to a rat perchloric acid-soluble protein (PSP), a mouse heat-responsive protein (Hrp12) and a goat tumor antigen (UK114). Sequence analysis revealed a GC-rich promoter with several consensus sequences for transcription factors, but no TATA- and CAAT-box. To confirm promoter activity, DNA fragments of the p14.5 5'-flanking region were ligated in front of the luciferase gene and were transfected into HeLa and HepG2 cells. A minimal promoter between nt -104 and nt +88 relative to the transcription start site was responsible for basal activity. Furthermore, we observed a head-to-head orientation of p14.5 to the gene for the protein subunit of RNase P and MRP ribonucleoproteins (hPOP1). Luciferase assays with fragments of the hPOP1 5'-flanking region revealed a minimal promoter between nt -20 and nt +98 relative to the start of transcription. These data indicate that the 102 bp region between p14.5 and hPOP1 can act as a bidirectional promoter. The p14.5-hPOP1-cluster was mapped to chromosome 8q22 using in situ hybridization technique.

Animals↗
PubMed1995

Dissociation constants and thermal stability of complexes of Bacillus intermedius RNase and the protein inhibitor of Bacillus amyloliquefaciens RNase.

Binase, the extracellular ribonuclease of Bacillus intermedius, is inhibited by barstar, the natural protein inhibitor of the homologous RNase, barnase, of B. intermedius. The dissociation constants of the binase complexes with barstar and its double Cys40,82Ala mutant are about 10(-12) M, only 5 to 43 times higher than those of the barnase-barstar complex. As with barnase, the denaturation temperature of binase is raised dramatically in the complex. Calorimetric studies of the formation and stability of the binase-barstar complex show that the binase reaction with barstar is qualitatively similar to that of barnase but some significant quantitative differences are reported.

Bacillus↗