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

Transcription factor NF-kappaB is essential for the induction of nitric oxide synthase (NOS) II (iNOS) by bacterial lipopolysaccharide in murine macrophages (Xie, Q. W., Kashiwabara, Y., and Nathan, C. (1994) J. Biol. Chem. 269, 4705-4708). In 3T3 fibroblasts, agents other than cytokines are efficacious inducers of NOS II expression. In addition to cytokines such as interferon-gamma or tumor necrosis factor-alpha, protein kinase C-stimulating agents such as tetradecanoylphorbol-13-acetate, or cyclic AMP-elevating agents such as forskolin and 8-bromo-cAMP markedly increased NOS II mRNA (measured by Sl nuclease and RNase protection analyses), NOS II protein (determined by Western blotting), and NOS activity (measured by chemiluminescence detection of NO2-). Transforming growth factor-beta1 (which is an inhibitor of NOS II induction in other cell types) potentiated NOS II mRNA expression produced by all inducing agents listed, whereas dexamethasone, pyrrolidine dithiocarbamate and 3,4-dichloroisocoumarin (inhibitors of NF-kappaB activation) suppressed NOS II mRNA induction in response to all stimulants. In electrophoretic mobility shift assays, nuclear protein extracts from 3T3 cells stimulated with any of the inducing agents significantly slowed the migration of an NF-kappaB-binding oligonucleotide, whereas nuclear extracts from untreated control cells did not. These experiments indicate that NF-kappaB is the key control element for the induction of NOS II in response to at least three different second messenger pathways in 3T3 cells.
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PMID:In murine 3T3 fibroblasts, different second messenger pathways resulting in the induction of NO synthase II (iNOS) converge in the activation of transcription factor NF-kappaB. 862 88

We suggest here that Porphyromonas gingivalis DNA may function as a virulence factor in periodontal disease through expression of inflammatory cytokine. The bacterial DNA markedly stimulated in a dose-dependent manner interleukin-6 (IL-6) production by human gingival fibroblasts. The stimulatory action was eliminated by treatment with DNase but not RNase. The stimulatory effect was not observed in the fibroblasts treated with eucaryotic DNAs. The bacterial DNA also stimulated in dose- and treatment time-dependent manners the expression of the IL-6 gene in the cells. In addition, the stimulatory effect was eliminated when the DNA was methylated with CpG motif methylase. Interestingly, a 30-base synthetic oligonucleotide containing the palindromic motif GACGTC could stimulate expression of the IL-6 gene and production of its protein in the cells. Furthermore, the synthetic oligonucleotide-induced expression of this cytokine gene was blocked by pyrrolidine dithiocarbamate and N-acetyl-L-cystine, potent inhibitors of transcriptional factor NF-kappaB. Gel mobility shift assay showed increased binding of NF-kappaB to its consensus sequence in the synthetic oligonucleotide-treated cells. Also, using specific antibody against p50 and p65, which compose NF-kappaB, we showed the consensus sequence-binding proteins to be NF-kappaB. These results are the first to demonstrate that the internal CpG motifs in P. gingivalis DNA stimulate IL-6 expression in human gingival fibroblasts via stimulation of NF-kappaB.
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PMID:CpG motifs in Porphyromonas gingivalis DNA stimulate interleukin-6 expression in human gingival fibroblasts. 1045 72

Cells respond to genotoxic stress by activation of many genes, including the tumor suppressor p53. p53 activates transcriptionally target genes, such as p21waf1 and gadd45, which can lead to cell cycle arrest, or bax, which can lead to cell death. We examined the response to genotoxic stress in two hematopoietic cell lines that harbor either wild-type (MOLT-4) or a mutant p53 with a codon 161 mutation (U266). We adapted a multiprobe RNase protection assay (RPA) to determine the steady-state RNA levels, and in combination with nuclear runoff assays, transcriptional rates of multiple stress-induced genes. We found a differential activation of growth arrest and cell death-specific p53 target genes in cells with wild-type or mutant p53. Our results show that genotoxic stress can activate the p21waf1 and gadd45 genes in both cell lines. However, the bax gene was not induced in U266 cells. Bax and gadd45 gene induction could be efficiently blocked by pretreating the cells with the antioxidant compound pyrrolidine dithiocarbamate, suggesting that oxidative stress was involved in these responses. Induction of all three genes in MOLT-4 cells was clearly at the transcriptional level, because we detected transcriptional activity by nuclear runoff RPA assays, and transfection with a consensus p53 binding sequence. U266 cells did not activate the same reporter, in spite of the upregulation of p21waf1 and gadd45 RNA levels. However, the p21waf1-reporter constructs containing 0.9 to 2.4 kb of the native p21 promoter were potently activated in U266 cells. These results indicate a differential regulation of p53 target genes in cells containing wild-type or codon 161 mutant p53.
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PMID:Differential upregulation of p53-responsive genes by genotoxic stress in hematopoietic cells containing wild-type and mutant p53. 1079 22

Six 5'-deoxy-5'-morpholine, piperidine, and pyrrolidine of pyrimidine nucleosides have been synthesized and characterized. Their inhibitory action to ribonuclease A has been studied by biochemical analysis and X-ray crystallography. These compounds are moderate inhibitors of RNase A with mid-to-upper micromolar inhibition constants (K(i)). The high resolution X-ray crystal structures of the RNase A-inhibitor complexes have shown that all inhibitors bind at the enzyme catalytic cleft with the pyrimidine nucleobase at the B(1)R(2) subsites while the 5' group binds away from the main subsite P(1), where P-O(5') bond cleavage occurs, toward the solvent close to subsite P(0). Structure-activity relationship analysis has demonstrated that the compounds with the larger group in the 5' position are more potent. Comparative structural analysis of these RNase A complexes with other similar RNase A-ligand complexes provides a structural explanation of their potency and suggests ways to improve their efficiency and selectivity. These inhibitors can be the starting point for the development of compounds that can be used as pharmaceuticals against pathologies associated with RNase A homologues such as human angiogenin, which is implicated in tumor induced neovascularization.
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PMID:Morpholino, piperidino, and pyrrolidino derivatives of pyrimidine nucleosides as inhibitors of ribonuclease A: synthesis, biochemical, and crystallographic evaluation. 1917 62