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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Molecular hybridisation using a ricin cDNA probe has revealed that the ricin/Ricinus communis agglutinin (RCA) multigene family is composed of approximately eight members. Several genomic clones containing preproricin and preproricin-like sequences have been isolated. Partial analysis of three different genomic clones by DNA sequencing and ribonuclease protection has indicated that at least three members of the lectin gene family are non-functional. None of the original seventeen positive clones isolated appears to contain a Ricinus communis agglutinin (RCA) gene. One gene member analysed (pCBG3H1) represents a functional ricin gene similar in coding sequence to the published cDNA sequence and possesses typical eukaryotic consensus sequences and seed-specific elements within the flanking sequences. Investigation at the transcriptional level of the expression pattern of this gene revealed that mRNA accumulates during the post-testa stages of seed development. The pattern of accumulation of steady-state transcripts correlates closely with that previously observed at the protein and translatable RNA levels.
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PMID:The lectin gene family of Ricinus communis: cloning of a functional ricin gene and three lectin pseudogenes. 137 5

Protein kinase C (PKC), a widely-distributed enzyme implicated in the regulation of many physiological processes, consists of a family of at least twelve isoenzymes which differ in tissue distribution, subcellular localization, regulatory properties, etc. In addition to this heterogeneity at the protein level, we identify here for the first time a PKC zeta pseudogene (psi PKC zeta) transcript, specifically expressed in the brain, which is identical with PKC zeta except for sequence divergence within the first variable domain (V1). The authenticity of this unique V1 sequence (V1') in mRNA was confirmed by RNase protection and reverse transcriptase PCR (RT-PCR) analysis. When translated in-frame with PKC zeta, a stop codon is located 28 amino acids towards the N-terminus of the divergence point and the intervening sequence lacks an expected initiating methionine. psi PKC zeta is non-functional in terms of protein synthesis since Western blotting with an antibody directed against the C-terminus of PKC zeta failed to reveal a protein smaller than PKC zeta, and synthetic psi PKC zeta RNA failed to support protein synthesis in a translation system in vitro. PCR amplification of rat genomic DNA demonstrated lack of an intron at the junction between V1' and the first constant domain (the V1'-C1 border), and genomic DNA Southern blot analysis using PKC zeta and psi PKC zeta-specific probes indicated that they have different loci. psi PKC zeta, therefore, is not derived from the PKC zeta gene by alternative splicing, but rather is the product of a distinct gene. In Northern blot analysis, brain PKC zeta mRNA was identified as a low-abundance 3.1 kb transcript, while the abundant 2.5 and 4.7 kb mRNAs previously reported to encode PKC zeta are, in fact, psi PKC zeta transcripts. Analysis of rat brain, heart, lung, liver, kidney and skeletal muscle revealed psi PKC zeta mRNA only in brain. PKC zeta transcripts were most abundant in lung and kidney (2.7 and 4.7 kb mRNAs), correlating with the tissue profile of PKC zeta immunoreactivity in Western blots. Probes complementary to the common V5 and C1 domains detected both PKC zeta and psi PKC zeta transcripts. Interestingly, the C1 probe also detected an abundant novel 1.75 kb mRNA in brain and heart, suggesting the existence of an additional PKC zeta-related species. This work, therefore, also emphasizes the importance of careful choice of oligonucleotide and cDNA probes to study PKC zeta mRNA.
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PMID:Identification of a brain-specific protein kinase C zeta pseudogene (psi PKC zeta) transcript. 757 16

Eosinophil cationic protein (ECP) is a toxin secreted by activated human eosinophils that has anti-parasitic, antibacterial, and neurotoxic activities; ECP also has ribonuclease activity and structural homology to other mammalian ribonucleases. To determine the relationship between the ribonuclease activity and cytotoxicity of ECP, a method for producing recombinant ECP (rECP) in a prokaryotic expression system was devised. Periplasmic isolates from induced bacterial transfectants contained enzymatically active rECP; micromolar concentrations of rECP were shown to be toxic for Staphylococcus aureus (strain 502A). In contrast, recombinant eosinophil-derived neurotoxin, with 67% amino acid sequence identity to ECP, had little to no toxicity for S. aureus; these findings are analogous to those obtained with purified, granule-derived ECP and eosinophil-derived neurotoxin. Two single base pair mutations were introduced into the coding sequence of rECP (Lys38 to Arg and His128 to Asp) to convert ribonuclease active-site residues into non-functional counterparts. These mutations eliminated the ribonuclease activity of rECP but had no discernible effect on the antibacterial activity of this protein, demonstrating that ribonuclease activity and cytotoxicity are, in this case, independent functions of ECP.
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PMID:Recombinant human eosinophil cationic protein. Ribonuclease activity is not essential for cytotoxicity. 771 81

The structure of the complex of ribonuclease from Streptomyces aureofaciens (RNase Sa) with exo guanosine 2',3'-cyclophosphorothioate has been refined against 0.2-nm resolution synchrotron data using, as a starting model, coordinates from the RNase Sa: 2'-GMP complex. The refinement was based on all data over 1.0-0.2 nm and converged to a crystallographic R factor of 11.9%. This is the first structure of a microbial ribonuclease complexed with a 2',3'-cyclophosphorothioate, which is a thio analogue of the intermediate of the two-step reaction. However, exo guanosine 2',3'-cyclophosphorothioate is bound in a non-functional mode and is not hydrolysed. This structure therefore does not provide direct evidence on the identity of the amino acid residues responsible for catalytic cleavage of the substrate. However, based on present and previous results, a plausible model is proposed for the complex of the cyclic intermediate which acts as substrate for the second step of the catalysis.
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PMID:Complex of ribonuclease Sa with a cyclic nucleotide and a proposed model for the reaction intermediate. 839 32

We have characterized four novel murine ribonuclease genes that, together with the murine eosinophil-associated ribonucleases 1 and 2, form a distinct and unusual cluster within the RNase A gene superfamily. Three of these genes (mR-3, mR-4, mR-5) include complete open reading frames, encoding ribonucleases with eight cysteines and appropriately spaced histidines (His11 and His124) and lysine (Lys35) that are characteristic of this enlarging protein family; the fourth sequence encodes a non-functional pseudogene (mR-6P). Although the amino acid sequence similarities among these murine ribonucleases varies from 60 to 94%, they form a unique cluster, as each sequence is found to be more closely related to another of this group than to either murine angiogenin or to murine pancreatic ribonuclease. Interestingly, the relationship between the six genes in this 'mR cluster' and the defined lineages of the RNase A gene family could not be determined by amino acid sequence homology, suggesting the possibility that there are one or more additional ribonuclease lineages that have yet to be defined. Although the nature of the evolutionary constraints promoting this unusual expansion and diversification remain unclear, the implications with respect to function are intriguing.
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PMID:Molecular cloning of four novel murine ribonuclease genes: unusual expansion within the ribonuclease A gene family. 933 52

Sam68 is a target of the c-Src tyrosine kinase. We previously showed that overexpression of Sam68 functionally substitutes for, as well as synergies with, HIV-1 Rev in Rev-response element (RRE)-mediated gene expression and virus replication. Here we describe the identification of heterogeneous nuclear ribonucleoprotein K (hnRNP K) as a protein that specifically interacts with Sam68 in vitro and in vivo. HnRNP K did not bind to RRE-RNA directly, but formed a super complex with Sam68 and RRE in vitro. RNase treatment did not change the strength of binding of hnRNP K to Sam68. We demonstrated that hnRNP K significantly inhibited Sam68-mediated, but not Rev-mediated, RRE-dependent gene expression. We further showed that Sam68, but not a non-functional mutant Sam68p21, inhibited transcriptional activation of CT element by hnRNP K. Interestingly, the Sam68p21 with a single amino acid substitution in the nuclear localization domain exhibited less affinity for hnRNP K in vitro. We propose that the direct interaction of Sam68 and hnRNP K adversely affect the activities of both proteins in signal transduction pathways of both transcriptional and post-transcriptional events.
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PMID:Functional interaction of Sam68 and heterogeneous nuclear ribonucleoprotein K. 1237 Aug 8

Self-compatible cultivars of Japanese apricot ( Prunus mume Shieb. et Zucc.), a tree species that normally shows S-RNase-based self-incompatiblity, have a horticultural advantage over self-incompatible cultivars. Inheritance of self-compatibility and a common S(f)-RNase allele that is observed in self-compatible cultivars was investigated using progenies from controlled crosses. Total DNAs were isolated from the parents and progenies of seven crosses that included at least one self-compatible cultivar as a parent. These DNAs were PCR-amplified with the Pru-C2 and PCE-R primer pair to determine S-haplotypes of the parents and progenies. A novel S-haplotype, S(8), was found. In all crosses examined, the S(f)-RNase gene was inherited from either the seed or pollen parent as a pistil S-allele in a non-functional S-haplotype. Self-compatibility of about 20 trees each from reciprocal crosses of 'Benisashi ( S(7) S(f))' and 'Shinpeidayu ( S(3) S(f))', and 26 selections from 16 different crosses was tested by pollination and pollen-tube growth studies. Cosegregation of the S(f)-RNase allele and self-compatibility was confirmed with all but selection 1K0-26 ( S(3) S(7)). Selection 1K0-26 ( S(3) S(7)) that originated from 'Benisashi ( S(7) S(f))' x 'Koshinoume ( S(3) S(f))' appeared to be self-compatible even without the S(f)-RNase allele. The possible role of pollen- S, a presumably existing pollen component of gametophytic self-incompatibility, is discussed.
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PMID:Inheritance of S(f)-RNase in Japanese apricot ( Prunus mume) and its relation to self-compatibility. 1258 23

This study characterizes the S6m-haplotype, a mutated S6-haplotype with an altered HindIII cut site, of sour cherry (Prunus cerasus). Inheritance and pollination studies of S-haplotypes from reciprocal crosses between 'Erdi Botermo' (EB; S4S6mSa) and 'Rheinische Schattenmorelle' (RS; S6SaSbSc) revealed that the S6m-haplotype conferred unilateral incompatibility with a non-functional pistil component and a functional pollen component. Expression analyses of S6-RNase and SFB6, a candidate gene for pollen-S, in the S6m-haplotype showed that SFB6 was transcribed in EB pollen, but S6-RNase was not transcribed in EB styles. These results were consistent with data from the inheritance and pollination studies. Inverse PCR for the flanking regions of S6-RNase in the S6- and S6m-haplotypes revealed an approximately 2600 bp insertion present at approximately 800 bp upstream of the S6-RNase in the S6m-haplotype, which is responsible for the alternation of the HindIII cut site and a possible cause of inhibition of the transcription of S6-RNase. SFB6 was present downstream of S6-RNase in both the S6- and S6m-haplotypes and expressed in the same way, supporting the idea that SFB is a good candidate for pollen-S in Prunus.
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PMID:Self-incompatibility (S) locus region of the mutated S6-haplotype of sour cherry (Prunus cerasus) contains a functional pollen S allele and a non-functional pistil S allele. 1451 82

Tetraploid sour cherry (Prunus cerasus) exhibits a genotype-dependent loss of gametophytic self-incompatibility that is caused by the accumulation of non-functional S-haplotypes with disrupted pistil component (stylar-S) and/or pollen component (pollen-S) function. Genetic studies using diverse sour cherry germplasm identified non-functional S-haplotypes for which an equivalent wild-type S-haplotype was present in sweet cherry (Prunus avium), a diploid progenitor of sour cherry. In all cases, the non-functional S-haplotype resulted from mutations affecting the stylar component S-RNase or Prunus pollen component S-haplotype-specific F-box protein (SFB). This study determines the molecular bases of three of these S-haplotypes that confer unilateral incompatibility, two stylar-part mutants (S(6m2) and S(13m)) and one pollen-part mutant (S(13)'). Compared to their wild-type alleles, S(6m2)-RNase has a 1 bp deletion, S(13m) -RNase has a 23 bp deletion and SFB(13)' has a 1 bp substitution that lead to premature stop codons. Transcripts were identified for these three alleles, S(6m2)-RNase, S(13m)-RNase, and SFB(13)', however, these transcripts presumably result in altered proteins with a resulting loss of activity. Our characterization of natural pollen-part and stylar-part mutants in sour cherry along with other natural S-haplotype mutants identified in Prunus supports the view that loss of pollen specificity and stylar rejection evolve independently and are caused by structural alterations affecting the S-haplotype. The prevalence of non-functional S-haplotypes in sour cherry but not in sweet cherry (a diploid) suggests that polyploidization and gene duplication were indirectly responsible for the dysfunction of some S-haplotypes and the emergence of self-compatibility in sour cherry. This resembles the specific mode of evolution in yeast where accelerated evolution occurred to one member of the duplicated gene pair.
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PMID:Molecular characterization of three non-functional S-haplotypes in sour cherry (Prunus cerasus). 1691 17

African trypanosomes are the causative agent of sleeping sickness. The therapeutics used to control and treat the disease are very ineffective and thus, the development of improved drugs is urgently needed. Recently, new strategies for the design of novel trypanocidals have been put forward. Among them are techniques that rely on parasite-specific RNA aptamers. One approach involves the aptamer-directed transport of lytic compounds to the lysosome of the parasite. The aptamer has been termed 2-16 RNA and here we report the optimization of the RNA for its applications in vivo. To convert aptamer 2-16 into a serum-stable reagent 2'-deoxy-2'-F- and/or 2'-deoxy-2'-NH(2)-uridine- and cytidine-substituted RNAs were generated. While 2'-NH(2)-dC/dU-modified RNAs were RNase-resistant, they were functionally inactive. By contrast, 2'-F-dC/dU-substituted 2-16 RNA retained its ability to bind to live trypanosomes (K(d)=45 nM) and was routed to the lysosome identically to unmodified RNA. 2'-F-dC/dU-substituted 2-16 RNA is thermostable (T(m)=75 degrees C) and has a serum half-life of 3.4 days. Furthermore, aptamer 2-16 was site-specifically PEGylated to increase its serum retention time. Conjugation with PEG polymers < or = 10 kDa only marginally impacted the binding characteristics of the RNA, while the addition of higher molecular mass PEG molecules resulted in non-functional aptamers. Together, the data provide optimized conjugation chemistries for the large-scale production of substituted aptamer 2-16 preparations with improved in vivo functionality.
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PMID:Post-SELEX chemical optimization of a trypanosome-specific RNA aptamer. 1822 May 40


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