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1.
以携带谷胱甘肽转移酶(GST)和过氧化氢酶(CAT1)的转基因水稻和非转基因水稻(Oryza sativa L.) 品种'中花11'的根系为材料, 比较分析了二者在PEG 6000、38℃及PEG 6000和38℃复合胁迫下抗氧化系统特别是抗坏血酸-谷胱甘肽循环系统的变化.结果显示, 6% PEG处理时,转基因水稻的CAT、GST、超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)和脱氢抗坏血酸还原酶(DHAR)的活性都显著高于非转基因水稻;38℃处理时,前者的CAT、GST、SOD和GR的活性则显著低于后者;6% PEG和38℃复合处理时,前者的CAT、GST、抗坏血酸过氧化物酶(APX)和DHAR的活性也都显著高于后者,但前者的SOD和GR活性则显著低于后者.6%PEG 诱导的转基因水稻根系的抗坏血酸氧还状态显著低于非转基因水稻,但二者的谷胱甘肽氧还状态无显著差异; 而6% PEG和38℃同时处理时,转基因水稻的谷胱甘肽氧还状态则显著高于非转基因水稻,但二者的抗坏血酸氧还状态差异不显著.研究发现,干旱和高温复合胁迫时,转基因水稻和非转基因水稻的抗氧化组分的变化均不等于这2种单一胁迫的叠加;GST和CAT1基因的转入对水稻抗氧化系统内源功能相关组分尤其是抗坏血酸-谷胱甘肽循环系统产生了一定的影响,两种水稻的根系可能利用不同的抗氧化组分调节机制对这些胁迫做出应答. 相似文献
2.
Different Responses of Plant Growth and Antioxidant System to the Combination of Cadmium and Heat Stress in Transgenic and Non-transgenic Rice 总被引:1,自引:0,他引:1
A comparative study of just cadmium (Cd) or heat and their combination treatments on some physiological parameters and the antioxidant systems in transgenic rice ( Oryza sativa L. cv. Zhonghua No.11) carrying glutathione-S-transferase (GST, EC. 2.5.1.18) and catalase1 (CAT1, EC. 1.11.1.6) and non-transgenics was conducted. The results revealed improved resistance in the transgenics to Cd and the combined Cd and heat stress than non-transgenics. Data showed that the activities of CAT, GST, superoxide dismutase (EC.1.15.1.1) and all components of the ascorbate-glutathione cycle measured in the stressed transgenics shoots are significantly different from those of non-transgenics. Results indicated that co-expression of GST and CAT1 had an important effect on the antioxidant system, in particular, the whole ascorbate-glutathione cycle. The less oxidative damage induced by Cd and the stress combination in the transgenics resulted not only from the GST and CAT1 transgene but also from the coordination of the whole ascorbate-glutathione cycle. 相似文献
3.
《植物学报(英文版)》2009,51(1)
A comparative study of just cadmium (Cd) or heat and their combination treatments on some physiological parameters and the antioxidant systems in transgenic rice (Oryza sativa L. cv. Zhonghua No.11) carrying glutathione-S-transferase (GST, EC. 2.5.1.18) and catalase1(CAT1, EC. 1.11.1.6) and non-transgenics was conducted. The results revealed improved resistance in the transgenics to Cd and the combined Cd and heat stress than non-transgenics. Data showed that the activities of CAT, GST, superoxide dismutase (EC.1.15.1.1) and all components of the ascorbate-glutathione cycle measured in the stressed transgenics shoots are significantly different from those of non-transgenics. Results indicated that co-expression of GST and CAT1 had an important effect on the antioxidant system, in particular, the whole ascorbate-glutathione cycle. The less oxidative damage induced by Cd and the stress combination in the transgenics resulted not only from the GST and CAT1 transgene but also from the coordination of the whole ascorbate-glutathione cycle. 相似文献
4.
The recommended field dose (RFD) of isoproturon induced significant accumulations of H2O2 in the leaves of 10-d-old maize seedlings throughout the following 20 d; the accumulation increased with time and also with
herbicide dose. Meanwhile, low doses significantly increased ascorbic acid, glutathione and thiols while high doses caused
diminutions. Superoxide dismutase (SOD; EC 1.15.1.1) activity was significantly enhanced up to the 12th d whereas ascorbate
peroxidase (APX; EC 1.11.1.7) activity was significantly reduced after the fourth d onwards. Catalase (CAT; EC 1.11.1.6) and
guaiacol peroxidase (GPX; EC 1.11.1.7) activities were similarly increased during the first 4 d but decreased from the 12th
and the eighth d, respectively. Low doses increased SOD and GPX activities but high doses led to diminutions whereas CAT and
APX were reduced by all doses. The activities of γ-glutamyl-cysteine synthethase (γ-GCS; EC 6.3.2.2) and glutathione synthethase
(GSS; EC 6.3.2.3) were enhanced for 4 d; high doses caused general reductions. Isoproturon significantly reduced activities
of glutathione S-transferase (GST; EC 2.5.1.18) isoforms [GST(CDNB), GST(ALA), or GST(MET)] after the fourth d, however, it had no effect on GST(ATR). Similar reductions in activities of glutathione peroxidase (GSPX; EC 1.15.1.1) and glutathione reductase (GR; EC 1.6.4.2)
were detected up to the 16th and the 12th d, respectively. The activities of GST isoforms, GSPX and GR were reduced by high
doses. These changes seemed to be related and might point to an oxidative stress state that exacerbated with prolonged time
and/or increased isoproturon dose. 相似文献
5.
干旱高温胁迫下转基因水稻的生理变化 总被引:6,自引:3,他引:3
用PEG-6000、38℃及PEG-6000+38℃胁迫处理携带谷胱甘肽转移酶(GST)和过氧化氢酶(CAT1)的转基因水稻和非转基因水稻(Oryza sativa L.cv中花11), 并比较分析了二者在胁迫下的生理指标和抗氧化酶活性变化.结果显示,在单一PEG及PEG和高温复合胁迫下,植株生长、光合参数和相对含水量的降低幅度及H2O2和MDA(malon dialdehyde)的积累量在非转基因水稻与转基因水稻之间都有显著差异.在这2种胁迫下,转基因水稻的可溶性糖含量及CAT和POD (Peroxidase) 活性与非转基因水稻也有显著差异.这些结果表明,谷胱甘肽转移酶(GST)和过氧化氢酶(CAT1)的表达减轻了转基因水稻在单一干旱及干旱+高温复合胁迫下的伤害. 相似文献
6.
Root growth and modifications of ROS-scavenging systems were investigated in transgenic rice (Oryza sativa L., cv. Zhonghua no. 11) co-expressing glutathione-S-transferase (GST, EC. 2.5.1.18) and catalase 1 (CAT1, EC 1.11.1.6) and
nontransgenic rice exposed to just salt or heat and their combination. The higher number of adventitious roots but the lower
root to shoot ratio were observed in the stressed transgenics as compared with nontransgenics. Most antioxidant enzymes, such
as CAT, GST, ascorbate peroxidase (APX, EC 1.11.1.11), glutathione reductase (GR, EC.1.6.4.2), dehydroascorbate reductase
(DHAR, EC.1.8.5.1), and the redox state of glutathione and ascorbate, measured in the transformant roots, were significantly
different from those in nontransformant roots following the three types of stress. The variations of root growth and antioxidant
systems in the stressed transgenic rice may be attributed to not only the GST and CAT1 transgenes but also the coordination
of the ascorbate-glutathione cycle. 相似文献
7.
Zhenfei Guo Meiyan Huang Shaoyun Lu Zhao Yaqing Qiao Zhong 《Acta Physiologiae Plantarum》2007,29(1):39-46
The responses of antioxidative system and photosystem II photochemistry of rice (Oryza sativa L.) to paraquat induced oxidative stress were investigated in a chilling-tolerant cultivar Xiangnuo no. 1, and a chilling-susceptible
cultivar, IR-50. Electrolyte leakage and malondialdehyde (MDA) content of Xiangnuo no. 1 were little affected by paraquat,
but they increased in IR-50. After paraquat treatment, superoxide dismutase (SOD) activity remained high in Xiangnuo no. 1,
while it declined in IR-50. Activities of catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) declined
with oxidative stress in both cultivars, but Xiangnuo no. 1 had higher GR activity than IR-50. Under paraquat induced oxidative
stress, ascorbic acid (AsA) and reduced glutathione (GSH) concentrations remained high in Xiangnuo no. 1, but decreased in
IR-50. The results indicated that higher activities of SOD and GR and higher contents of AsA and GSH in Xiangnuo no. 1 under
paraquat induced oxidative stress were associated with its tolerance to paraquat, while paraquat induced damage to IR-50 was
related to decreased activities of SOD, APX and GR and contents of AsA and GSH. F
v/F
m, Φ
PSII, and qP remained high in Xiangnuo no. 1, while they decreased greatly in IR-50 under paraquat induced oxidative stress. 相似文献
8.
Salt stress is one of the most serious factors limiting the productivity of agricultural crops. Increasing evidence has demonstrated that vacuolar Na+/H+ antiporters play a crucial role in plant salt tolerance. In the present study, we expressed the Suaeda salsa vacuolar Na+/H+ antiporter SsNHX1 in transgenic rice to investigate whether this can increase the salt tolerance of rice, and to study how overexpression of this gene affected other salt-tolerant mechanisms. It was found that transgenic rice plants showed markedly enhanced tolerance to salt stress and to water deprivation compared with non-transgenic controls upon salt stress imposition under outdoor conditions. Measurements of ion levels indicated that K+, Ca2+ and Mg2+ contents were all higher in transgenic plants than in non-transformed controls. Furthermore, shoot V-ATPase hydrolytic activity was dramatically increased in transgenics compared to that of non-transformed controls under salt stress conditions. Physiological analysis also showed that the photosynthetic activity of the transformed plants was higher whereas the same plants had reduced reactive oxygen species generation. In addition, the soluble sugar content increased in the transgenics compared with that in non-transgenics. These results imply that up-regulation of a vacuolar Na+/H+ antiporter gene in transgenic rice might cause pleiotropic up-regulation of other salt-resistance-related mechanisms to improve salt tolerance.Fengyun Zhao and Zenglan Wang contributed equally to this work. 相似文献
9.
Accumulation and oxidative stress biomarkers in Japanese flounder larvae and juveniles under chronic cadmium exposure 总被引:1,自引:0,他引:1
Liang Cao Wei Huang Jinhu Liu Xuebo Yin Shuozeng Dou 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2010,151(3):386-392
This study investigated how Cd exposure affected oxidative biomarkers in Japanese flounder, Paralichthys olivaceus, at early life stages (ELS). Fish were exposed to waterborne Cd (0–48 µg L− 1) from embryonic to juvenile stages for 80 days. Growth, Cd accumulation, activities of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione S-transferase (GST, EC 2.5.1.18), and levels of glutathione (GSH) and lipid peroxidation (LPO) were investigated at three developmental stages. Flounder growth decreased and Cd accumulation increased with increasing Cd concentration. In metamorphosing larvae, CAT and SOD activities were inhibited and GSH level was elevated, while LPO was enhanced by increasing Cd concentrations. CAT and GST activities of settling larvae were inhibited but GSH level was elevated at high Cd concentrations. In juveniles, SOD activity and LPO level were increased but GST activity was inhibited as Cd concentration increased. Antioxidants in flounder at ELS were able to develop ductile responses to defend against oxidative stress, but LPO fatally occurred due to Cd exposure. These biochemical parameters could be used as effective oxidative biomarkers for evaluating Cd contamination and toxicity in marine environments: CAT, SOD, GSH, and LPO for metamorphosing stage; CAT, GSH, and GST for settling stage; and SOD, GST, and LPO for juvenile stage. 相似文献
10.
Abstract Isoproturon at the recommended field dose (RFD) significantly reduced fresh and dry weights of shoots and roots as well as chlorophyll and carotenoid contents of 10-day-old maize seedlings during the following 20 days. The higher the herbicide dose, the greater the reduction. Meanwhile, ascorbate (AsA) and reduced glutathione (GSH) increased in leaves for only the first few days. Similar increases in activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) were detected. Low doses caused general increases while high doses induced diminutions; however, CAT and APX activities were inhibited by all doses. Nevertheless, H2O2 was significantly accumulated throughout the experiment; the magnitude of accumulation increased with time and herbicide dose. On the contrary, there were significant inhibitions in activities of the glutathione S-transferase (GST) isoforms (GST(CDNB), GST(ALA), or GST(MET)) with no variation in GST(ATR); the inhibition was greater with increasing isoproturon doses. These findings suggest the occurrence of an oxidative stress induced by isoproturon, a state that prolonged with increasing herbicide dose and/or treatment time. Moreover, V max of GST was lowered by isoproturon, whereas K m was unchanged, indicating that the herbicide is a competitive inhibitor of GST. 相似文献
11.
12.
Transgenic tobacco plants overexpressing cotton glutathione S-transferase (GST) show enhanced resistance to methyl viologen 总被引:6,自引:0,他引:6
A GST (EC 2.5.1.18) gene (Gst-cr 1) from cotton was introduced into Nicotiana tabacum by Agrobacterium tumefaciens-mediated transformation. Transgenic tobacco plants overexpressing Gst-cr1 were normal in growth and mature compared with control, but had much higher levels of GST and GPx activities and showed an enhanced resistance to oxidative stress induced by a low concentration of methyl viologen (MV). Six antioxidant enzymes, glutathione S-transferase, glutathione peroxidase (EC 1.11.1.9), superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6), and ascorbate peroxidase (EC 1.11.1.11) were monitored in transgenic lines and non-transgenic control during MV treatments. When they were treated with 0.03 mmol/L of MV, both transgenic lines and control showed a rapid increase in the activities of GST, GPx, SOD, POD, APx, while the activity of CAT seemed to be irregular. The percent of the increase in SOD and POD activities was much higher in control than in transgenic plants. When treated with 0.05 mmol/L of MV, both control and transgenic plants were severely damaged, and the activities of the six enzymes decreased sharply. 相似文献
13.
Toshikazu Takesawa Minako Ito Hiroyuki Kanzaki Nanako Kameya Ikuo Nakamura 《Molecular breeding : new strategies in plant improvement》2002,9(2):93-101
To develop a rice cultivar that would be suitable for direct-seedingcultivation in cooler temperate regions, we generated transgenic rice plants inwhich a rice encoding a -class glutathioneS-transferase (GST) under the control of a maize ubiquitinpromoter. GSTs have been suggested to be responsible for tolerance to variousstresses such as cold, salt and drought by detoxification of xenobioticcompounds and reactive oxygen species. A total of 87 R0 transgenicrice plants harboring a chimeric GST gene were generatedusing Agrobacterium mediated transformation. ThreeR2 lines homozygous for the transgene were assayed for GST activityand had higher GST and glutathione peroxidase activities thannon-transformants.Seedlings of the transgenic lines demonstrated greatly enhanced germination andgrowth rates at low temperature grown under submergence. The GST transgeniclines should be useful for breeding rice cultivars suitable for direct-seedingcultivation in cooler temperate regions. 相似文献
14.
In the present work, the response of tobacco (Nicotiana tabaccum L.) wild-type SR1 and transgenic CAT1AS plants (with a basal reduced CAT activity) was evaluated after exposure to the herbicide
paraquat (PQ). Superoxide anion (O2.−) formation was inhibited at 3 or 21 h of exposure, but H2O2 production and ion leakage increased significantly, both in SR1 or CAT1AS leaf discs. NADPH oxidase activity was constitutively
57% lower in non-treated transgenic leaves than in SR1 leaves and was greatly reduced both at 3 or 21 h of PQ treatment. Superoxide
dismutase (SOD) activity was significantly reduced by PQ after 21 h, showing a decrease from 70% to 55%, whereas catalase
(CAT) activity decreased an average of 50% after 3 h of treatment, and of 90% after 21 h, in SR1 and CAT1AS, respectively.
Concomitantly, total CAT protein content was shown to be reduced in non-treated CAT1AS plants compared to control SR1 leaf
discs at both exposure times. PQ decreased CAT expression in SR1 or CAT1AS plants at 3 and 21 h of treatment. The mechanisms
underlying PQ-induced cell death were possibly not related exclusively to ROS formation and oxidative stress in tobacco wild-type
or transgenic plants. 相似文献
15.
Banerjee J Das N Dey P Maiti MK 《Biochemical and biophysical research communications》2010,402(4):637-643
Our recent report documented that the rice germin-like protein1 (OsGLP1), being a cell wall-associated protein involves in disease resistance in rice and possesses superoxide dismutase (SOD) activity as recognized by heterologous expression in tobacco. In the present study, the transgenic tobacco plants were analyzed further to decipher the detailed physiological and biochemical functions of the OsGLP1 and its associated SOD activity. The transgenic tobacco lines expressing SOD-active OsGLP1 showed tolerance against biotic and abiotic stresses mitigated by hyper-accumulating H2O2 upon infection by fungal pathogen (Fusarium solani) and treatment to chemical oxidizing agent (ammonium persulfate), respectively. Histological staining revealed enhanced cross-linking of the cell wall components in the stem tissues of the transgenic plants. Fourier transform infrared spectroscopy (FTIR) analysis of the biopolymer from the stem tissues of the transgenic and untransformed plants revealed differential banding pattern of the spectra corresponding to various functional groups. Our findings demonstrate that the OsGLP1 with its inherent SOD activity is responsible for hyper-accumulation of H2O2 and reinforcement of the cell wall components. 相似文献
16.
Foliar spraying ofArabidopsis thaliana (Columbia ecotype) plants with a 1.0-mM salicylic acid (SA) solution significantly improved their tolerance to subsequent
paraquat (PQ)-induced oxidative damage. Leaf injuries, including losses of chlorophyll, protein, and fresh weight, were reduced.
Our analysis of antioxidant enzymes in the leaves showed that SA pre-treatment effectively retarded rapid decreases in the
activities of Superoxide dismutase (SOD), catalase, and ascorbate peroxidase that are normally associated with PQ exposure.
In addition, guaiacol peroxidase activity was remarkably increased. In a native gel assay of peroxidase (POD) isozymes, staining
activity of the POD1 isozyme, which disappeared in plants exposed only to 10 μM PQ, was significantly recovered by the 1.0-mM
SA pre-treatment POD2 isozyme activity was also pronounced in all SA-treated plants compared with the control. A 12-h SA pre-treatment,
without subsequent PQ stress, also caused a small increase in the endogenous H2O2 content that accompanies the symptoms of mild leaf injuries. This enhanced level occurred in parallel with a slight SOD increase
and a catalase decrease. From our results, it can be assumed that, due to the small increase in SOD as well as catalase inactivation
via SA pre-treatment, a moderate increase in H2O2 levels may occur. In turn, a large induction of guaiacol peroxidase leads to enhanced PQ tolerance inA. thaliana plants. 相似文献
17.
Jeonghoon Han Eun-Ji Won Dae-Sik Hwang Jae-Sung Rhee Il-Chan Kim Jae-Seong Lee 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2013,158(2):91-100
Glutathione S-transferases (GSTs; EC 2.5.1.18) are major enzymes that function in Phase II detoxification reactions by catalyzing the conjugation of reduced glutathione through cysteine thiol. In this study, we cloned and sequenced four GST genes from the monogonont rotifer Brachionus koreanus. The domain regions of four Bk-GSTs showed a high similarity to those of other species. In addition, to evaluate the potential of GST genes as an early warning signal for oxidative stress, we exposed sublethal concentrations of copper (Cu) to B. koreanus and measured glutathione (GSH) contents and several antioxidant enzymes such as glutathione S-transferase (GST), glutathione peroxidase (GPx; EC 1.11.1.9), and glutathione reductase (GR; EC 1.8.1.7). The reactive oxygen species (ROS) at 12 h and 24 h after copper exposure increased significantly. GSH contents however did not increase significantly and even it decreased at 0.24 mg/L at 12 h. The activities of several antioxidant enzymes, particularly GPx and GR, showed a dramatic increase in 0.24 mg/L of CuCl2. Messenger RNAs of each Bk-GST showed different patterns of modulations according to GST types, and particularly, Bk-GST-omega, Bk-GST-sigma, and Bk-GST zeta genes were highly sensitive to Cu. These results indicate that Bk-GSTs, functioning as one of the enzymatic defense mechanisms particularly in the early stage of oxidative stress response, were induced by Cu exposure. This also suggests that these genes and related enzymes have a potential as biomarkers for a more sensitive initial stress response. 相似文献
18.
Kyong-Suk Kang Chang-Jin Lim Tae-Jin Han Joon-Chul Kim Chang-Duck Jin 《Journal of Plant Biology》1999,42(3):187-193
The changes in isozyme profiles of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase
(GR) during severe deactivation of total CAT activity by aminotriazole (AT) treatment were investigated in the leaves ofArabidopsis thaliana (Columbia ecotype) in relation to H2O2-mediated oxidative stress. In spite of striking deactivation of total CAT activity by 0.1 mM AT, there were no significant
differences in H2O2 levels or total leaf soluble protein contents including a Rubisco in both the control and AT-treated leaves. On the other
hand, one specific protein band (molecular mass, 66 kD) was observed on the SDS-gel from leaf soluble proteins whose staining
intensity was strikingly enhanced by AT treatment for 6 h. However, this band disappeared at 12 h. In the native-gel assays
of CAT, POD, APX and GR isozymes, AT remarkably inhibited the expression of the CAT1 isozyme with no effects on CAT2 and CAT3,
and generally had no effect on POD isozyme profiles. However, AT stimulated the intensity of activities of pre-existing APX1
and GR1 isozymes. In particular, it induced a new synthesis of one GR isozyme. Therefore, these results collectively suggest
that a striking deactivation of total CAT activity by AT inA. thaliana leaves largely results from the suppression of CAT1 isozyme, and that APX1, GR1, and a newly synthesized GR isozyme could
complement the role of CAT1 to metabolize H2O2 into non-toxic water. 相似文献
19.
Overexpression of bacterial catalase in tomato leaf chloroplasts enhances photo-oxidative stress tolerance 总被引:1,自引:0,他引:1
E.-A. MOHAMED T. IWAKI I. MUNIR M. TAMOI S. SHIGEOKA & A. WADANO 《Plant, cell & environment》2003,26(12):2037-2046
The Escherichia coli gene katE, which is driven by the promoter of the Rubisco small subunit gene of tomato, rbcS3C, was introduced into a tomato (Lycopersicon esculentum Mill.) by Agrobacterium tumefaciens‐mediated transformation. Catalase activity in progeny from transgenic plants was approximately three‐fold higher than that in wild‐type plants. Leaf discs from transgenic plants remained green at 24 h after treatment with 1 µm paraquat under moderate light intensity, whereas leaf discs from wild‐type plants showed severe bleaching after the same treatment. Moreover, ion leakage from transgenic leaf discs was significantly less than that from wild‐type leaf discs at 24 h after treatment with 1 µm paraquat and 10 mm H2O2, respectively, under moderate light intensity. To evaluate the efficiency of the E. coli catalase to protect the whole transgenic plant from the oxidative stress, transgenic and wild‐type plants were sprayed with 100 µm paraquat and exposed to high light illumination (800 µmol m?2 s?1). After 24 h, the leaves of the transgenic plants were less damaged than the leaves of the wild‐type plants. The catalase activity and the photosynthesis activity (indicated by the Fv/Fm ratio) were less affected by paraquat treatment in leaves of transgenic plants, whereas the activities of the chloroplastic ascorbate peroxidase isoenzymes and the ascorbate content decreased in both lines. In addition, the transgenic plants showed increased tolerance to the oxidative damage (decrease of the CO2 fixation and photosystem II activity and increase of the lipid peroxidation) caused by drought stress or chilling stress (4 °C) under high light intensity (1000 µmol m?2 s?1). These results indicate that the expression of the catalase in chloroplasts has a positive effect on the protection of the transgenic plants from the photo‐oxidative stress invoked by paraquat treatment, drought stress and chilling stress. 相似文献
20.
Yani Zou Chih‐Hsin Chen John R. Fike Ting‐Ting Huang 《Genesis (New York, N.Y. : 2000)》2009,47(3):142-154
The extracellular isoform of superoxide dismutase (EC‐SOD, Sod3) plays a protective role against various diseases and injuries mediated by oxidative stress. To investigate the pathophysiological roles of EC‐SOD, we generated tetracycline‐inducible Sod3 transgenic mice and directed the tissue‐specific expression of transgenes by crossing Sod3 transgenic mice with tissue‐specific transactivator transgenics. Double transgenic mice with liver‐specific expression of Sod3 showed increased EC‐SOD levels predominantly in the plasma as the circulating form, whereas double transgenic mice with neuronal‐specific expression expressed higher levels of EC‐SOD in hippocampus and cortex with intact EC‐SOD as the dominant form. EC‐SOD protein levels also correlated well with increased SOD activities in double transgenic mice. In addition to enabling tissue‐specific expression, the transgene expression can be quickly turned on and off by doxycycline supplementation in the mouse chow. This mouse model, thus, provides the flexibility for on–off control of transgene expression in multiple target tissues. genesis 47:142–154, 2009. © 2009 Wiley‐Liss, Inc. 相似文献