Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 5'-flanking region of the Saccharomyces cerevisiae catalase T gene (CTT1) and the part of the gene coding for the N-terminus of catalase T were sequenced. 5'-Ends of transcripts of the region were located by S1 nuclease mapping and primer extension. To analyse control elements in the upstream region, a CTT1-lacZ gene fusion was constructed. Deletion analysis was carried out within a part of the 5'-flanking region showing homology to the upstream region of the yeast CYC1 gene. Like the CTT1 gene, this gene is controlled by heme, oxygen and glucose. The results obtained show that the CTT1 gene is positively controlled by heme. Tentative evidence has been obtained for the involvement of upstream sequences homologous to UAS1 and UAS2 of the CYC1 gene in heme control. Further, a negative site has been located between the upstream activator sites and the transcription start. Within this negative region a ten base-pair sequence was detected that shows high homology to a sequence located within a negative control region of the CYC1 gene and some homology to the negative control elements of the S. cerevisiae CAR1 and CAR2 genes.
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PMID:Heme control region of the catalase T gene of the yeast Saccharomyces cerevisiae. 242 50

DNA-protein and DNA interstrand cross-links were induced in isolated chromatin after treatment with H2O2 and ferrous ethylenediaminetetraacetate (EDTA). Retention of DNA on membrane filters after heating of chromatin in a dissociating solvent indicated the presence of a stable linkage between DNA and protein. Treatment of protein-free DNA with H2O2/Fe2+-EDTA did not result in enhanced filter retention. Incubation of cross-linked chromatin with proteinase K completely eliminated filter retention. Resistance to S1 nuclease after a denaturation-renaturation cycle was used to detect DNA interstrand cross-links. Heating the treated chromatin at 45 degrees C for 16 h and NaBH4 reduction enhanced the extent of interstrand cross-linking. The following data are consistent with, but do not totally prove, the hypothesis that cross-links are induced by hydroxyl radicals generated in Fenton-type reactions: (1) cross-linking was inhibited by hydroxyl radical scavengers; (2) the degree of inhibition of DNA interstrand cross-links correlated very closely with the rate constants of the scavengers for reaction with hydroxyl radicals; (3) cross-linking was eliminated or greatly reduced by catalase; (4) the extent of cross-linking was directly related to the concentration of Fe2+-EDTA. Partial inhibition of cross-linking by superoxide dismutase indicates that superoxide-driven Fenton chemistry is involved. The data indicate that DNA cross-linking may play a role in the manifestation of the biological activity of agents or systems that generate reactive hydroxyl radicals.
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PMID:Deoxyribonucleic acid-protein and deoxyribonucleic acid interstrand cross-links induced in isolated chromatin by hydrogen peroxide and ferrous ethylenediaminetetraacetate chelates. 629 97

Previous reports have described several maize lines whose developmental patterns of catalase gene expression vary from the "typical" maize line, W64A. Among these variants are the lines A16 and A338, both found to be null for the CAT-2 protein. Identification of a third CAT-2 null line, designated A340, is described. RNA blots and S1 nuclease protection analysis indicate that all three CAT-2 null lines produce a similarly shortened Cat2 transcript. The molecular basis for this aberrant Cat2 transcript is discussed.
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PMID:Molecular basis for the CAT-2 null phenotype in maize. 860 25

Intracellular pathogenic bacteria, including Mycobacterium tuberculosis, frequently have multitiered defense mechanisms ensuring their survival in host phagocytic cells. One such defense determinant in M. tuberculosis is the katG gene, which encodes an enzyme with catalase, peroxidase, and peroxynitritase activities. KatG is considered to be important for protection against reactive oxygen and nitrogen intermediates produced by phagocytic cells. However, KatG also activates the front-line antituberculosis drug isoniazid, hence rendering M. tuberculosis exquisitely sensitive to this compound. In this context, katG expression represents a double-edged sword, as it is an important virulence determinant but at the same time its activity levels determine sensitivity to INH. Thus, it is important to delineate the regulation and expression of katG, as this not only can aid understanding of how M. tuberculosis survives and persists in the host but also may provide information of relevance for better management of INH therapy. Here, we report the first extensive analysis of the katG promoter activity examined both in vitro and in vivo. Using S1 nuclease protection analysis, we mapped the katG mRNA 5' ends and demonstrated that two promoters, P(1)furA and P(1)katG, control transcription of katG. The furA and katG genes are cotranscribed from P(1)furA. Both P(1)furA and P(1)katG promoters show induction upon challenge with hydrogen peroxide and cumene hydroperoxide. Studies carried out using the transcriptional fusions P(1)furA-gfp, P(1)katG-gfp, and P(1)furA-P(1)katG-gfp confirmed the existence of two katG promoters. In addition, we showed that both promoters are expressed in vivo during intracellular growth of virulent M. tuberculosis H37Rv. P(1)furA is induced early upon infection, and P(1)katG becomes active only upon extended growth in macrophages. These studies delineate the transcriptional organization of the furA-katG region and indicate differential regulation in vivo of the two katG promoters. These phenomena most likely reflect the differing demands at sequential stages of the infection cycle and may provide information for improved understanding of host-pathogen interactions in tuberculosis and for further optimization of INH chemotherapy.
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PMID:Mapping of Mycobacterium tuberculosis katG promoters and their differential expression in infected macrophages. 1139 68

The expression of peroxisome proliferator-activated receptors alpha (PPARalpha) and gamma (PPARgamma) was studied in the human adenocarcinoma Caco-2 cells induced to differentiate by long term culture (15 days). The differentiation of Caco-2 cells was attested by increases in the activities of sucrase-isomaltase and alkaline phosphatase (two brush border enzymes), fatty acyl-CoA oxidase (AOX) and catalase (two peroxisomal enzymes), by an elevation in the protein levels of villin (a brush border molecular marker), AOX, peroxisomal bifunctional enzyme (PBE), catalase and peroxisomal membrane protein of 70 kDa (PMP70). and by the appearance of peroxisomes. The expression of PPARalpha and PPARgamma was investigated by Western blotting, immunocytochemistry, Northern blotting and S1 nuclease protection assay during the differentiation of Caco-2 cells. The protein levels of PPARalpha, PPARgamma, and PPARgamma2 increased gradually during the time-course of Caco-2 cell differentiation. Immunocytochemistry revealed that PPARalpha and gamma were localized in cell nuclei. The PPARgamma1 protein was encoded by PPARgamma3 mRNA because no signal was obtained for PPARgamma1 mRNA using a specific probe in S1 nuclease protection assay. The amount of PPARgamma3 mRNA increased concomitantly to the resulting PPARgamma1 protein. On the other hand, the mRNA of PPARalpha and PPARgamma2 were not significantly changed, suggesting that the increase in their respective protein was due to an elevation of the translational rate. The role played by the PPAR subtypes in Caco-2 cell differentiation is discussed.
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PMID:Expression of peroxisome proliferator-activated receptors alpha and gamma in differentiating human colon carcinoma Caco-2 cells. 1200 Jan 43

The vernacular name 'fluorescent Pseudomonas group 97-514' was coined for a group of 43 strains isolated from two French natural mineral waters. All these strains were gram-negative, rod-shaped and motile by means of a single polar flagellum. They produced fluorescent pigment (pyoverdin) on King B medium, catalase and cytochrome oxidase. They were capable of respiratory but not fermentative metabolism. They were not able to accumulate poly-beta-hydroxybutyrate and possessed an arginine dihydrolase system. DNA-DNA relatedness studies (S1 nuclease method) showed that the 43 strains of 'fluorescent Pseudomonas group 97-514' formed a genetically homogeneous group (DNA-DNA relatedness ranged from 70 to 100%). A total of 76 strains representing well-known or partially characterized species of the genus Pseudomonas sensu stricto had 7-56% DNA hybridization with strain CFML 97-514T. The highest DNA binding values were found with Pseudomonas veronii CIP 104663T (52%), Pseudomonas rhodesiae CIP 104664T (56%), Pseudomonas marginalis ATCC 10844T (56%), Pseudomonas gessardii CIP 105469T (53%) and Pseudomonas cedrella CIP 105541T (52%). Their unrelatedness was confirmed by deltaTm values greater than 7 degrees C. On the basis of the results of phenotypic and DNA-DNA hybridization studies, a novel Pseudomonas species, Pseudomonas grimontii sp. nov., is proposed for the 43 strains of 'fluorescent Pseudomonas group 97-514'. The type strain is strain CFML 97-514T (= CIP 106645T = ATCC BAA-140T). The G+C content of the DNA of the type strain was 58 mol%. A comparison of the complete 16S rRNA gene sequence of the type strain CFML 97-514T and the sequence of other strains of the genus Pseudomonas revealed that the novel species fell within the 'Pseudomonas fluorescens intrageneric cluster'. Members of P. grimontii grew at 4 degrees C but not at 41 degrees C. They were able to use D-xylose, alpha-L-rhamnose, alpha-aminobutyrate, meso-erythritol and itaconate as sole sources of carbon and energy and formed levan from sucrose. Strains do not possess lecithinase or Tween esterase activities. The clinical significance of P. grimontii is unknown.
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PMID:Pseudomonas grimontii sp. nov. 1236 Dec 51

KatA is the major catalase required for hydrogen peroxide (H2O2) resistance and acute virulence in Pseudomonas aeruginosa PA14, whose transcription is governed by its dual promoters (katAp1 and katAp2). Here, we observed that KatA was not required for acute virulence in another wild type P. aeruginosa strain, PAO1, but that PAO1 exhibited higher KatA expression than PA14 did. This was in a good agreement with the observation that PAO1 was more resistant than PA14 to H2O2 as well as to the antibiotic peptide, polymyxin B (PMB), supposed to involve reactive oxygen species (ROS) for its antibacterial activity. The higher KatA expression in PAO1 than in PA14 was attributed to both katAp1 and katAp2 transcripts, as assessed by S1 nuclease mapping. In addition, it was confirmed that the PMB resistance is attributed to both katAp1 and katAp2 in a complementary manner in PA14 and PAO1, by exploiting the promoter mutants for each -10 box (p1m, p2m, and p1p2m). These results provide an evidence that the two widely used P. aeruginosa strains display different virulence mechanisms associated with OxyR and Anr, which need to be further characterized for better understanding of the critical virulence pathways that may differ in various P. aeruginosa strains.
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PMID:Differential expression of the major catalase, KatA in the two wild type Pseudomonas aeruginosa strains, PAO1 and PA14. 3118 16