Mammalian enzymes for preventing transcriptional errors caused by oxidative damage

Biomolecular Engineering Research Institute Suita, Osaka 565-0874, Japan.
Nucleic Acids Research (Impact Factor: 9.11). 02/2005; 33(12):3779-84. DOI: 10.1093/nar/gki682
Source: PubMed


8-Oxo-7,8-dihydroguanine (8-oxoGua) is produced in cells by reactive oxygen species normally formed during cellular metabolic processes. This oxidized base can pair with both adenine and cytosine, and thus the existence of this base in messenger RNA would cause translational errors. The MutT protein of Escherichia coli degrades 8-oxoGua-containing ribonucleoside di- and triphosphates to the monophosphate, thereby preventing the misincorporation of 8-oxoGua into RNA. Here, we show that for human the MutT-related proteins, NUDT5 and MTH1 have the ability to prevent translational errors caused by oxidative damage. The increase in the production of erroneous proteins by oxidative damage is 28-fold over the wild-type cells in E.coli mutT deficient cells. By the expression of NUDT5 or MTH1 in the cells, it is reduced to 1.4- or 1.2-fold, respectively. NUDT5 and MTH1 hydrolyze 8-oxoGDP to 8-oxoGMP with V(max)/K(m) values of 1.3 x 10(-3) and 1.7 x 10(-3), respectively, values which are considerably higher than those for its normal counterpart, GDP (0.1-0.5 x 10(-3)). MTH1, but not NUDT5, possesses an additional activity to degrade 8-oxoGTP to the monophosphate. These results indicate that the elimination of 8-oxoGua-containing ribonucleotides from the precursor pool is important to ensure accurate protein synthesis and that both NUDT5 and MTH1 are involved in this process in human cells.

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    • "). Regarding the sanitization enzymes of nucleotide pools, mammalian cells have multiple MutT-type enzymes, such as MTH1 and -2 as well as NUDT5, not only in the cytosol, but also in the nucleus and mitochondria (Yoshimura et al. 2003, Ishibashi et al. 2005, Nakabeppu et al. 2010). On the other hand, AtNUDX1 is only localized in the cytosol and is the sole MutT-type enzyme that eliminates oxidized nucleotides in Arabidopsis plants (Yoshimura et al. 2007). "
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    ABSTRACT: Oxidized nucleotides produced by oxidative stress cause DNA mutations and the production of abnormal proteins. Thus, mammalian cells have developed multiple MutT-type Nudix hydrolases that exhibit pyrophosphohydrolase activity toward oxidized nucleotides in the cytosol, mitochondria, and nucleus. On the other hand, AtNUDX1 is the only MutT-type Nudix hydrolase in the cytosol of Arabidopsis plants. To clarify the physiological significance of the defenses against oxidatively-induced DNA damages in plant organelles, we analyzed the effects of the ectopic expression of the human MutT-type Nudix hydrolase, hMTH1, which was localized in the cytosol (cyt-hMTH1), chloroplasts (chl-hMTH1), and mitochondria (mit-hMTH1) of Arabidopsis cells, on tolerance to oxidative stress. Tolerance to oxidative stress caused by heating and the PQ treatment was higher in the mit-hMTH1 and chl-hMTH1 plants than in the control and cyt-hMTH1 plants. The accumulation of H2O2 and the frequency of dead cells were lower in the mit-hMTH1 and chl-hMTH1 plants under stressful conditions. The poly(ADP-ribosyl)ation (PAR) reaction, which regulates repair systems for damaged DNA, was activated in the mit-hMTH1 and chl-hMTH1 plants under heat stress and the PQ treatment. Furthermore, DNA fragmentation, which caused programmed cell death, was clearly suppressed in the mit-hMTH1 and chl-hMTH1 plants under heat stress. These results demonstrated that the ectopic expression of hMTH1 in the chloroplasts and mitochondria of Arabidopsis enhanced oxidative stress tolerance by activating the PAR reaction and suppressing programmed cell death.
    Plant and Cell Physiology 06/2014; 55(9). DOI:10.1093/pcp/pcu083 · 4.93 Impact Factor
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    • "NUDT5, which was down-regulated in TNF-␣-treated JMJD3- kd THP-1 cells, has an important role in the hydrolysis of 8-oxo guanosine diphosphate to 8-oxo guanosine monophosphate and therefore prevention of misincorporation of 8-oxo guanosine into RNA. The 8-oxo guanosine containing nucleotides can be incorporated into RNA or DNA, which can cause transcriptional and replicational errors, respectively (Ishibashi et al., 2005). In addition , recently, Zhang et al. (2012) reported that the cell cycle G1 phase was significantly delayed and that the cell numbers in both S and G2/M phases were reduced by NUDT5 suppression through induction of key proteins that prevent the G1-S transition, including p53, p16 and Rb. "
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    ABSTRACT: JMJD3, a Jumonji C family histone demethylase, plays an important role in the regulation of inflammation induced by the transcription factor nuclear factor-kappa B (NF-κB) in response to various stimuli. JMJD3 is a histone-3 lysine-27 trimethylation (H3K27me3) demethylase, a histone mark associated with transcriptional repression and activation of a diverse set of genes. The present study assessed stable JMJD3 knockdown (KD)-dependent proteomic profiling in human leukemia monocyte (THP-1) cells to analyze the JMJD3-mediated differential changes of marker expression in inflammatory cells. To analyze the protein expression profile of tumor necrosis factor-alpha (TNF-α)-stimulated JMJD3-kd THP-1 cells, we employed matrix-assisted-laser-desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Additionally, Ingenuity Pathways Analysis (IPA) was applied to establish the molecular networks. A comparative proteomic profile was determined in TNF-α-treated both of JMJD3-kd THP-1 cells and THP-1 scrambled (sc) cells. The expression of tripartite motif protein (TRIM5), glutathione peroxidase (GPx), glia maturation factor-γ (GMFG), caspase recruitment domain family, member 14 (CARMA2), and dUTP pyrophosphatase were significantly down-regulated, whereas heat shock protein beta-1 (HspB1) and prohibition were significantly up-regulated in JMJD3-kd THP-1 cells. The molecular and signaling networks of the differentially expressed proteins in JMJD3-kd THP-1 cells were determined by IPA. The molecular network signatures and functional proteomics obtained in this study may facilitate the suppression of different key inflammatory regulators through JMJD3-attenuation, which would be crucial to evaluate potential therapeutic targets and to elucidate the molecular mechanism of JMJD3-kd dependent effects in THP-1 cells.
    Molecular Immunology 05/2013; 56(1-2):113-122. DOI:10.1016/j.molimm.2013.04.013 · 2.97 Impact Factor
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    • "The marker for oxidative stress, 8-hydroxyguanine is highly mutagenic because it pairs with adenine as well as cytosine. These properties cause partial phenotypic suppression during transcription as well as transversion mutations during DNA replication [41]. It is likely that the error proteins, produced as a result of the altered genetic information, therefore, are identified as foreign molecules and play a role as neo-epitopes [42,43]. "
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    ABSTRACT: Background Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the destruction of bone and cartilage. Although its etiology is unknown, the hydroxyl radical has been suggested to be involved in the pathogenesis of RA. Recently, molecular hydrogen (H2) was demonstrated to be a selective scavenger for the hydroxyl radical. Also, the method to prepare water containing extremely high concentration of H2 has been developed. We hypothesized that H2 in the water could complement conventional therapy by reducing the oxidative stress in RA. Methods Twenty patients with rheumatoid arthritis (RA) drank 530 ml of water containing 4 to 5 ppm molecular hydrogen (high H2 water) every day for 4 weeks. After a 4-week wash-out period, the patients drank the high H2 water for another 4 weeks. Urinary 8-hydroxydeoxyguanine (8-OHdG) and disease activity (DAS28, using C-reactive protein [CRP] levels) was estimated at the end of each 4-week period. Results Drinking high H2 water seems to raise the concentration of H2 more than the H2 saturated (1.6 ppm) water in vivo. Urinary 8-OHdG was significantly reduced by 14.3% (p < 0.01) on average. DAS28 also decreased from 3.83 to 3.02 (p < 0.01) during the same period. After the wash-out period, both the urinary 8-OHdG and the mean DAS28 decreased, compared to the end of the drinking period. During the second drinking period, the mean DAS28 was reduced from 2.83 to 2.26 (p < 0.01). Urinary 8-OHdG was not further reduced but remained below the baseline value. All the 5 patients with early RA (duration < 12 months) who did not show antibodies against cyclic citrullinated peptides (ACPAs) achieved remission, and 4 of them became symptom-free at the end of the study. Conclusions The results suggest that the hydroxyl radical scavenger H2 effectively reduces oxidative stress in patients with this condition. The symptoms of RA were significantly improved with high H2 water.
    10/2012; 2(1):27. DOI:10.1186/2045-9912-2-27
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