Modulation of the Poly(ADP-ribosyl)ation Reaction via the Arabidopsis ADP-Ribose/NADH Pyrophosphohydrolase, AtNUDX7, Is Involved in the Response to Oxidative Stress
Modulation of the Poly(ADP-ribosyl)ation Reaction via the Arabidopsis ADP-Ribose/NADH Pyrophosphohydrolase, AtNUDX7, Is Involved in the Response to Oxidative Stress
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DOI：
10.1104/pp.109.140442
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发表时间：
2009-10-01
期刊：
影响因子：
7.4
通讯作者：
Shigeoka, Shigeru
中科院分区：
文献类型：
--
作者：
Ishikawa, Kazuya;Ogawa, Takahisa;Shigeoka, Shigeru
在这里，我们评估了在正常条件下和百草枯处理引起的氧化胁迫下，拟南芥（Arabidopsis thaliana）ADP核糖（Rib）/NADH焦磷酸水解酶AtNUDX 7（拟南芥NUDX 7）对AtNUDX 7过表达（Pro（35 S）：AtNUDX 7）或AtNUDX 7破坏（KO-nudx 7）植物中聚（ADP-核糖基）化（PAR）反应的调节。与对照植物相比，在Pro（35 S）：AtNUDX 7植物中NADH和ADP-Rib的水平降低，但在正常条件和氧化胁迫下在KO-nudx 7植物中增加，表明AtNUDX 7水解ADP-Rib和NADH作为生理底物。Pro（35S）：AtNUDX 7和KO-nudx 7植物表现出增加和降低的耐受性，分别与对照植物相比，氧化胁迫。Pro（35 S）：AtNUDX 7和KO-nudx 7植株中的poly（ADP-Rib）水平分别显著高于和低于对照植株中的那些。在Pro（35 S）：AtNUDX 7植物中，由氧化胁迫下PAR反应的活化引起的NAD+和ATP的消耗被完全抑制。在KO-nudx 7-和3-氨基苯甲酰胺处理的植物中观察到NAD+和ATP的积累，其中PAR反应被抑制。DNA修复因子AtXRCC 1和AtXRCC 2的表达水平（对于X射线修复交叉互补因子1和2），与正常条件和氧化应激下的AtNUDX 7相同，尽管在AtXRCC 3、AtRAD 51（对于大肠杆菌RecA同源物）、AtDMC 1（对于破坏的减数分裂cDNA）和AtMND 1（对于减数分裂核分裂）和AtNUDX 7的水平之间观察到负相关。这些结果表明，在正常条件下，AtNUDX 7通过NADH周转控制NADH和NAD（+）之间的平衡。在氧化应激下，AtNUDX 7通过从游离ADP-Rib分子中再循环核苷酸来提供ATP，从而维持NAD（+）水平，并因此通过调节PAR反应来调节针对氧化性DNA损伤的防御机制。
Here, we assessed modulation of the poly(ADP-ribosyl)ation (PAR) reaction by an Arabidopsis (Arabidopsis thaliana) ADPribose (Rib)/NADH pyrophosphohydrolase, AtNUDX7 (for Arabidopsis Nudix hydrolase 7), in AtNUDX7-overexpressed (Pro(35S):AtNUDX7) or AtNUDX7-disrupted (KO-nudx7) plants under normal conditions and oxidative stress caused by paraquat treatment. Levels of NADH and ADP-Rib were decreased in the Pro(35S):AtNUDX7 plants but increased in the KO-nudx7 plants under normal conditions and oxidative stress compared with the control plants, indicating that AtNUDX7 hydrolyzes both ADP-Rib and NADH as physiological substrates. The Pro(35S): AtNUDX7 and KO-nudx7 plants showed increased and decreased tolerance, respectively, to oxidative stress compared with the control plants. Levels of poly(ADP-Rib) in the Pro(35S): AtNUDX7 and KO-nudx7 plants were markedly higher and lower, respectively, than those in the control plants. Depletion of NAD+ and ATP resulting from the activation of the PAR reaction under oxidative stress was completely suppressed in the Pro(35S):AtNUDX7 plants. Accumulation of NAD+ and ATP was observed in the KO-nudx7- and 3-aminobenzamide-treated plants, in which the PAR reaction was suppressed. The expression levels of DNA repair factors, AtXRCC1 and AtXRCC2 (for x-ray repair cross-complementing factors 1 and 2), paralleled that of AtNUDX7 under both normal conditions and oxidative stress, although an inverse correlation was observed between the levels of AtXRCC3, AtRAD51 (for Escherichia coli RecA homolog), AtDMC1 (for disrupted meiotic cDNA), and AtMND1 (for meiotic nuclear divisions) and AtNUDX7. These findings suggest that AtNUDX7 controls the balance between NADH and NAD(+) by NADH turnover under normal conditions. Under oxidative stress, AtNUDX7 serves to maintain NAD(+) levels by supplying ATP via nucleotide recycling from free ADP-Rib molecules and thus regulates the defense mechanisms against oxidative DNA damage via modulation of the PAR reaction.