Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We hypothesize that poly(ADP-ribose) polymerase (PARP) activation is an important mechanism in the oxidative stress-related development of diabetic retinopathy. In the experiments reported here, we evaluated if: a) PARP activation is present in the retina in short-term diabetes; and b) PARP inhibitors, 3-aminobenzamide and 1,5-isoquinolinediol, counteract diabetes- and hypoxia-induced retinal VEGF formation. In vivo studies were performed in control and streptozotocin-diabetic rats treated with/without 3-aminobenzamide or 1,5-isoquinolinediol (30 and 3 mg/kg per day, intraperitoneally, for 2 weeks after 2 weeks of diabetes). In vitro studies were performed in human retinal pigment epithelial cells exposed to normoxia or hypoxia with/without 3-aminobenzamide and 1,5-isoquinolinediol at 200 and 2 micro M. Retinal immunostaining for poly(ADP-ribose) was increased and NAD concentration reduced in diabetic rats, and both variables were corrected by PARP inhibitors. Retinal VEGF protein (ELISA, immunohistochemistry), but not mRNA (ribonuclease protection assay) abundance, was increased in diabetic rats, and this increase was corrected by both 3-aminobenzamide and 1,5-isoquinolinediol. PARP inhibitors did not affect retinal glucose, sorbitol pathway intermediates or lipid peroxidation in diabetic rats. Hypoxia caused a several-fold increase in both VEGF-mRNA and protein in retinal pigment epithelial cells. VEGF mRNA overexpression was only slighly blunted by PARP inhibitors whereas VEGF protein was corrected. In conclusion, PARP is involved in diabetes- and hypoxia-induced VEGF production at post-transcriptional level, downstream from the sorbitol pathway activation and oxidative stress. The results justify studies of PARP inhibitors in models of retinopathy of prematurity and diabetic retinopathy.
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PMID:Poly(ADP-ribose) polymerase inhibitors counteract diabetes- and hypoxia-induced retinal vascular endothelial growth factor overexpression. 1520 16

Pseudomonas aeruginosa phage EL is a dsDNA phage related to the giant phiKZ-like Myoviridae. The EL genome sequence comprises 211,215 bp and has 201 predicted open reading frames (ORFs). The EL genome does not share DNA sequence homology with other viruses and micro-organisms sequenced to date. However, one-third of the predicted EL gene products (gps) shares similarity (Blast alignments of 17-55% amino acid identity) with phiKZ proteins. Comparative EL and phiKZ genomics reveals that these giant phages are an example of substantially diverged genetic mosaics. Based on the position of similar EL and phiKZ predicted gene products, five genome regions can be delineated in EL, four of which are relatively conserved between EL and phiKZ. Region IV, a 17.7 kb genome region with 28 predicted ORFs, is unique to EL. Fourteen EL ORFs have been assigned a putative function based on protein similarity. Assigned proteins are involved in DNA replication and nucleotide metabolism (NAD+-dependent DNA ligase, ribonuclease HI, helicase, thymidylate kinase), host lysis and particle structure. EL-gp146 is the first chaperonin GroEL sequence identified in a viral genome. Besides a putative transposase, EL harbours predicted mobile endonucleases related to H-N-H and LAGLIDADG homing endonucleases associated with group I intron and intein intervening sequences.
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PMID:Genome comparison of Pseudomonas aeruginosa large phages. 1625 35

1. ADP, ATP and GDP inhibited the phosphotransferase activity, the release of cyclic nucleotides from RNA, of ribonuclease. No significant inhibition was elicited by pyrimidine 5'-nucleoside diphosphates, CDP and UDP. 2. Inhibition by ADP, AMP, adenosine, adenine, NAD and NADP was insignificant at the concentrations tested. Small inhibition was observed with high concentrations of AMP and only when soluble RNA was the substrate. 3. Inhibition by ADP was found to be ;uncompetitive'. 4. Results seem to indicate that at least for optimum inhibition the polyphosphate of the purine nucleoside is essential. They further suggest that the inhibitor acts by combining with the enzyme only when the enzyme is bound to the substrate.
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PMID:Effect of nucleoside 5'-di- and 5'-tri-phosphates on pancreatic ribonuclease activity. 1674 35

Metabolic enzymes are usually characterized to have one specific function, and this is the case of UDP-glucose dehydrogenase that catalyzes the twofold NAD(+)-dependent oxidation of UDP-glucose into UDP-glucuronic acid. We have determined that this enzyme is also capable of participating in other cellular processes. Here, we report that the bacterial UDP-glucose dehydrogenase (UgdG) from Sphingomonas elodea ATCC 31461, which provides UDP-glucuronic acid for the synthesis of the exopolysaccharide gellan, is not only able to bind RNA but also acts as a ribonuclease. The ribonucleolytic activity occurs independently of the presence of NAD(+) and the RNA binding site does not coincide with the NAD(+) binding region. We have also performed the kinetics of interaction between UgdG and RNA. Moreover, computer analysis reveals that the N- and C-terminal domains of UgdG share structural features with ancient mitochondrial ribonucleases named MAR. MARs are present in lower eukaryotic microorganisms, have a Rossmannoid-fold and belong to the isochorismatase superfamily. This observation reinforces that the Rossmann structural motifs found in NAD(+)-dependent dehydrogenases can have a dual function working as a nucleotide cofactor binding domain and as a ribonuclease.
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PMID:Rossmann-fold motifs can confer multiple functions to metabolic enzymes: RNA binding and ribonuclease activity of a UDP-glucose dehydrogenase. 2313 39

An intimate link exists between circadian clocks and metabolism with nearly every metabolic pathway in the mammalian liver under circadian control. Circadian regulation of metabolism is largely driven by rhythmic transcriptional activation of clock-controlled genes. Among these output genes, Nocturnin (Noct) has one of the highest amplitude rhythms at the mRNA level. The Noct gene encodes a protein (NOC) that is highly conserved with the endonuclease/exonuclease/phosphatase (EEP) domain-containing CCR4 family of deadenylases, but highly purified NOC possesses little or no ribonuclease activity. Here, we show that NOC utilizes the dinucleotide NADP(H) as a substrate, removing the 2' phosphate to generate NAD(H), and is a direct regulator of oxidative stress response through its NADPH 2' phosphatase activity. Furthermore, we describe two isoforms of NOC in the mouse liver. The cytoplasmic form of NOC is constitutively expressed and associates externally with membranes of other organelles, including the endoplasmic reticulum, via N-terminal glycine myristoylation. In contrast, the mitochondrial form of NOC possesses high-amplitude circadian rhythmicity with peak expression level during the early dark phase. These findings suggest that NOC regulates local intracellular concentrations of NADP(H) in a manner that changes over the course of the day.
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PMID:Spatiotemporal regulation of NADP(H) phosphatase Nocturnin and its role in oxidative stress response. 3187 54


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