Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The enterobacterium Erwinia carotovora ssp. carotovora strain 71 (hereafter Ecc71) produces extracellular enzymes such as pectate lyase isozymes (Pels), cellulase (Cel), polygalacturonase (Peh) and protease (Prt). These enzymes degrade plant cell wall components and are largely responsible for the elicitation of soft-rot diseases in plants and plant products. Ecc71 also produces HarpinEcc, the elicitor of hypersensitive reaction (HR) and the quorum-sensing signal, N-(3-oxohexanoyl)-L-homoserine lactone (OHL). OHL controls extracellular enzyme and HarpinEcc production. The levels of these enzymes, as well as the expression of hrpNEcc, the structural gene for HarpinEcc, and ohll, the gene specifying OHL synthesis, are negatively regulated by RsmaA. rsmB, formerly aepH, on the other hand, positively regulates extracellular enzyme production. 6His-RsmA recombinant protein purified from E. coli binds rsmB RNA as indicated by gel mobility shift assays. rsmB comprises 547 bp DNA, which is transcribed from a single start site immediately after a sigma70-like promoter. In Ecc71, two rsmB RNA species are detected: a full-length 479 base rsmB RNA and a 259 base rsmB' RNA. rsmB' DNA hybridizes with the 259 base and the 479 base transcripts. A 3' RNase protection assay revealed that the 259 base and the 479 base RNA species end at the same position immediately after the putative rho-independent terminator. The expression of rsmB-lacZ transcriptional fusions established that the rsmB' RNA is not produced because of the activation of an internal promoter. These data strongly suggest that the 259 base rsmB' RNA is derived by processing of the primary rsmB RNA. In Ecc71, rsmB' expression driven by the lac promoter causes overproduction of Pel, Peh, Cel and Prt, and accumulation of pel-1, peh-1, hrpNEcc and ohll transcripts. By contrast, a plasmid with the rsmB' DNA sequence deleted fails to cause overproduction of the extracellular enzymes in Ecc71. The rsmB' effect also occurs in Escherichia coli as glycogen accumulation is stimulated in the presence of rsmB'. In vivo and in vitro translation as well as mutational analysis of rsmB' have established that rsmB' RNA does not yield a translational product. Therefore, we concluded that the rsmB' RNA itself functions as the regulator. Indeed, the expression rsmB' DNA leads to neutralization of the negative effects of the RNA-binding protein, RsmA, in Ecc71 and Serratia marcescens strain SM274. We propose a model that explains how RsmA and rsmB control the expression of genes for extracellular enzymes.
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PMID:Characterization of a novel RNA regulator of Erwinia carotovora ssp. carotovora that controls production of extracellular enzymes and secondary metabolites. 970 16

A mutant strain (CTNUX23) of Rhizobium etli carrying Tn5 unable to grow with sulfate as the sole sulfur source was isolated and characterized. Sequence analysis showed that Tn5 is inserted into a metZ (O-succinylhomoserine sulfhydrylase)-homologous gene. The CTNUX23 mutant strain had a growth dependency for methionine, although cystathionine or homocysteine, but not homoserine or O-succinylhomoserine, allowed growth of the mutant. RNase protection assays showed that the metZ-like gene had a basal level of expression in methionine- or cysteine-grown cells, which was induced when sulfate or thiosulfate was used. The metZ gene was cloned from the parent wild-type strain, CE3, and the resulting plasmid pAR204 relieved, after transformation, the methionine auxotrophy of both strains CTNUX23 of R. etli and PAO503(metZ) of Pseudomonas aeruginosa. Unlike strain CE3 or CTNUX23 (pAR204), strain CTNUX23 showed undetectable levels of O-succinylhomoserine sulfhydrylase activity. Strain CTNUX23 was unable to produce flavonoid-inducible lipo-chitin oligosaccharides (Nod factors) or to induce nodules or nodulelike structures on the roots of Phaseolus vulgaris, unless methionine was added to the growth medium. These data and our previous results support the notion that cysteine or glutathione, but not methionine, is supplied by the root cells to bacteria growing inside the plant.
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PMID:The Rhizobium etli metZ gene is essential for methionine biosynthesis and nodulation of Phaseolus vulgaris. 988 90

Conjugal transfer of Agrobacterium tumefaciens Ti plasmids is regulated by quorum sensing via TraR and its cognate autoinducer, N-(3-oxo-octanoyl)-L-homoserine lactone. We isolated four Tn5-induced mutants of A. tumefaciens C58 deficient in TraR-mediated activation of tra genes on pTiC58DeltaaccR. These mutations also affected the growth of the bacterium but had no detectable influence on the expression of two tester gene systems that are not regulated by quorum sensing. In all four mutants Tn5 was inserted in a chromosomal open reading frame (ORF) coding for a product showing high similarity to RNase D, coded for by rnd of Escherichia coli, an RNase known to be involved in tRNA processing. The wild-type allele of the rnd homolog cloned from C58 restored the two phenotypes to each mutant. Several ORFs, including a homolog of cya2, surround A. tumefaciens rnd, but none of these genes exerted a detectable effect on the expression of the tra reporter. In the mutant, traR was expressed from the Ti plasmid at a level about twofold lower than that in NT1. The expression of tra, but not the growth rate, was partially restored by increasing the copy number of traR or by disrupting traM, a Ti plasmid gene coding for an antiactivator specific for TraR. The mutation in rnd also slightly reduced expression of two tested vir genes but had no detectable effect on tumor induction by this mutant. Our data suggest that the defect in tra gene induction in the mutants results from lowered levels of TraR. In turn, production of sufficient amounts of TraR apparently is sensitive to a cellular function requiring RNase D.
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PMID:The Agrobacterium tumefaciens rnd homolog is required for TraR-mediated quorum-dependent activation of Ti plasmid tra gene expression. 1139 55

An increase in the nitric oxide (NO) biosynthesis in Lactobacillus plantarum 8P-A3 cells takes place under strong stress influence, which leads to a considerable decrease in the microbial cell viability: heating at 70 degrees C and 80 degrees C, prolonged cultivation, toxic effect of hexylresorcinol. The factors, which do not lead to cell death, such as heating at 60 degrees C, 50 microg/ml homoserine lactone, Bacillus intermedius 7P ribonuclease (binase) in concentrations up to 300 microg/ml, do not induce NO synthesis. The activation of the NO biosynthesis in response to stress treatment evidences to universality of key-mechanisms of stress response in cells differing in the level of their organization as well as to important role of nitric oxide in them.
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PMID:[Induction of the NO synthesis in lactobacilli under stress conditions]. 2270 41

The ribonucleases (RNases) E and J play major roles in E. coli and Bacillus subtilis, respectively, and co-exist in Sinorhizobium meliloti. We analysed S. meliloti 2011 mutants with mini-Tn5 insertions in the corresponding genes rne and rnj and found many overlapping effects. We observed similar changes in mRNA levels, including lower mRNA levels of the motility and chemotaxis related genes flaA, flgB and cheR and higher levels of ndvA (important for glucan export). The acyl-homoserine lactone (AHL) levels were also higher during exponential growth in both RNase mutants, despite no increase in the expression of the sinI AHL synthase gene. Furthermore, several RNAs from both mutants migrated aberrantly in denaturing gels at 300 V but not under stronger denaturing conditions at 1300 V. The similarities between the two mutants could be explained by increased levels of the key methyl donor S-adenosylmethionine (SAM), since this may result in faster AHL synthesis leading to higher AHL accumulation as well as in uncontrolled methylation of macromolecules including RNA, which may strengthen RNA secondary structures. Indeed, we found that in both mutants the N6-methyladenosine content was increased almost threefold and the SAM level was increased at least sevenfold. Complementation by induced ectopic expression of the respective RNase restored the AHL and SAM levels in each of the mutants. In summary, our data show that both RNase E and RNase J are needed for SAM homeostasis in S. meliloti.
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PMID:RNase E and RNase J are needed for S-adenosylmethionine homeostasis in Sinorhizobium meliloti. 2814 92