Peach(Prunus persica Batsch‘Yuhualu’)fruit are sensitive to chilling injury(CI).Proline,polyamine(PA),and nitric oxide(NO)are important small regulators of various metabolic pathways under chilling stress that mitig...Peach(Prunus persica Batsch‘Yuhualu’)fruit are sensitive to chilling injury(CI).Proline,polyamine(PA),and nitric oxide(NO)are important small regulators of various metabolic pathways under chilling stress that mitigate CI.Ethylene is known to promote senescence and CI,while 1-methylcyclopropene(1-MCP)is an antagonist that inhibits the effects of ethylene.However,how1-MCP and ethylene affect proline,PA,and NO levels under chilling stress remains unclear.To address these questions,1-MCP(1μL·L^(−1))and ethylene(1μL·L^(−1))treatments were applied to peach fruit.Fruit were stored at 4°C for 28 d,then moved to 25°C for 3 d immediately after cold storage.Peach fruit exhibited CI symptoms after 7 d of cold storage with enhanced electrolyte leakage and malondialdehyde contents.The 1-MCP treatment significantly(P<0.05)restrained peach CI,and fruit did not exhibit CI symptoms until 14 d of cold storage.Proline and PAs in peach under chilling stress weremostly synthesized from glutamate and arginine,which were catalyzed by1-pyrroline-5-carboxylate synthetase and arginine decarboxylase,respectively.1-MCPtreated fruit exhibited higher proline and PA contents and enhanced chilling tolerance compared to the control,while ethylene-treated fruit had lower proline and PA contents and reduced chilling tolerance.Ethylene-treated fruit,which exhibited more severe CI symptoms compared to the control,had significantly(P<0.05)lower NO contents and NO synthase activities.However,NOmay not be a direct acting factor in 1-MCPinduced chilling tolerance,as 1-MCP-treated fruit had lower NO contents and NO synthase activities compared to the control.In conclusion,proline and PA clearly played direct and important roles in 1-MCP-induced peach chilling tolerance,while NO may not be actively involved.展开更多
A series of novel aromatic-linked polyamine macrocyclic derivatives have been synthesized. Their structures were confirmed by MS and ^1H NMR. These compounds exhibited potent anti-HIV-1 activities.
<abstract>Aim: To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis. Methods: Male golden hamsters of 7-week-o...<abstract>Aim: To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis. Methods: Male golden hamsters of 7-week-old were kept under a light and dark cycle of 14 h and 10 h for 1 week to stimulate maximally the gonadal function. DES was injected subcutaneously at doses of 0.01 mg·kg-1·day-1, 0.1 mg·kg-1·day-1 and 1 mg·kg-1·day-1 for one week. Results: DES treatment caused a significant decrease in the weight of epididymis. The activity of epididymal ornithine decar boxylase (ODC) increased 1 day after DES treatment, kept at a high level for 4 days and then decreased to nearly normal level at day 7. The activity of spermidine/spermine N1-acetyltransferase (SSAT) also increased transiently after DES treatment. The contents of putrescine, spermidine, spermine and N1-acetylspermidine were increased 1 day -4 days after DES treatment and restored to normal at day 7. All these changes showed a marked difference between the caput and the cauda. Conclusion: The polyamine biosynthesis in the hamster epididymis can be affected by DES, a xenoestrogen. DES may probably affect polyamine metabolism in the epididymis by regulating the rate-limiting enzymes involved in the polyamine biosynthesis.展开更多
AIM: To investigate the expression of myofibrillogenesis regulator-1 (MR-1) in relation to clinicopathological parameters and postoperative survival in a group of Chinese patients with gastric cancer. METHODS: In our ...AIM: To investigate the expression of myofibrillogenesis regulator-1 (MR-1) in relation to clinicopathological parameters and postoperative survival in a group of Chinese patients with gastric cancer. METHODS: In our previous study of human wholegenome gene expression profiling, the differentially expressed genes were detected in the gastric cancer and its adjacent noncancerous mucosa. We found that MR-1 was associated with the location and differentiation of tumors. In this study, MR-1 protein expression was determined by immunohistochemistry in specimens of primary cancer and the adjacent noncancerous tissues from gastric cancer patients. A set of real-time quantitative polymerase chain reaction assays based on the Universal ProbeLibrary-a collection of 165 presynthesized, fluorescence-labeled locked nucleic acid hydrolysis probes-was designed specifically to detect the expression of MR-1 mRNA. The correlation was analyzed between the expression of MR-1 and other tumor characteristics which may influence the prognosis of gastric cancer patients. A retrospective cohort study on the prognosis was carried out and clinical data were collected from medical records. RESULTS: MR-1 mRNA and protein could be detected in gastric cancer tissues as well as in matched noncancerous tissues. MR-1 was up-regulated at both mRNA (5.459 ± 0.639 vs 1.233 ± 0.238, P < 0.001) and protein levels (34.2% vs 13.2%, P = 0.003) in gastric cancer tissues. Correlation analysis demonstrated that high expression of MR-1 in gastric cancer was significantly correlated with clinical stage (P = 0.034). Kaplan-Meier analysis showed that the postoperative survival of the MR-1 positive group tended to be poorer than that of the MR-1 negative group, and the difference was statistically significant (P = 0.002). Among all the patients with stageⅠ-Ⅳ carcinoma, the 5-year survival rates of MR-1 positive and negative groups were 50.40% and 12.70%, respectively, with respective median survival times of 64.27 mo (95%CI: 13.41-115.13) and 16.77 mo (95%CI: 8.80-24.74). Univariate and multivariate analyses were performed to compare the impact of MR-1 expression and other clinicopathological parameters on prognosis. In a univariate analysis on all 70 specimens, 6 factors were found to be significantly associated with the overall survival statistically: including MR-1 expression, depth of invasion, distant metastasis, lymph node metastasis, vascular invasion and the tumor node metastasis (TNM) stage based on the 7th edition of the International Union against Cancer TNM classification. To avoid the influence caused by univariate analysis, the expressions of MR-1 as well as other parameters were examined in multivariate Cox analysis. Clinicopathological variables that might affect the prognosis of gastric cancer patients were analyzed by Cox regression analysis, which showed that MR-1 expression and TNM stage were independent predictors of postoperative survival. The best mathematical multivariate Cox regression model consisted of two factors: MR-1 expression and TNM stage. Our results indicated that MR-1 protein could act as an independent marker for patient overall survival [Hazard ratio (HR): 2.215, P = 0.043]. CONCLUSION: MR-1 is an important variable that can be used to evaluate the outcome, prognosis and targeted therapy of gastric cancer patients.展开更多
The Ca^(2+)/CaM signal transduction pathway helps plants adapt to environmental stress. However, our knowledge on the functional proteins of C^(2+)/CaM pathway in peanut(Arachis hypogeae L.) remains limited. In the pr...The Ca^(2+)/CaM signal transduction pathway helps plants adapt to environmental stress. However, our knowledge on the functional proteins of C^(2+)/CaM pathway in peanut(Arachis hypogeae L.) remains limited. In the present study, a novel calmodulin 4(CaM4)-binding protein S-adenosyl-methionine synthetase 1(SAMS1) in peanut was identified using a yeast two-hybrid assay. Expression of AhSAMS1was induced by Ca^(2+), ABA, and salt stress. To elucidate the function of AhSAMS1, physiological and phenotypic analyses were performed with wild-type and transgenic materials. Overexpression of AhSAMS1increased spermidine and spermidine synthesis while decreased the contents of ethylene, thereby eliminating excessive reactive oxygen species(ROS) in transgenic lines under salt stress. AhSAMS1 reduced uptake of Na+and leakage of K+from mesophyll cells, and was less sensitive to salt stress during early seedling growth, in agreement with the induction of SOS and NHX genes Transcriptomics combined with epigenetic regulation uncovered relationships between differentially expressed genes and differentially methylated regions, which raised the salt tolerance and plants growth. Our findings support a model in which the role of AhSAMS1 in the ROS-dependent regulation of ion homeostasis was enhanced by Ca^(2+)/CaM while AhSAMS1-induced methylation was regulated by CaM, thus providing a new strategy for increasing the tolerance of plants to salt stress.展开更多
Studies have found that the phosphatase actin regulatory factor 1 expression can be related to stroke,but it remains unclear whether changes in phosphatase actin regulatory factor 1 expression also play a role in trau...Studies have found that the phosphatase actin regulatory factor 1 expression can be related to stroke,but it remains unclear whether changes in phosphatase actin regulatory factor 1 expression also play a role in traumatic brain injury.In this study we found that,in a mouse model of traumatic brain injury induced by controlled cortical impact,phosphatase actin regulatory factor 1 expression is increased in endothelial cells,neurons,astrocytes,and microglia.When we overexpressed phosphatase actin regulatory factor 1 by injection an adeno-associated virus vector into the contused area in the traumatic brain injury mice,the water content of the brain tissue increased.However,when phosphatase actin regulatory factor 1 was knocked down,the water content decreased.We also found that inhibiting phosphatase actin regulatory factor 1 expression regulated the nuclear factor kappa B signaling pathway,decreased blood-brain barrier permeability,reduced aquaporin 4 and intercellular adhesion molecule 1 expression,inhibited neuroinflammation,and neuronal apoptosis,thereby improving neurological function.The findings from this study indicate that phosphatase actin regulatory factor 1 may be a potential therapeutic target for traumatic brain injury.展开更多
Aromatic rice is considered an important commodity in the global market because of its strong aroma and eating and cooking quality.Asian countries,such as India and Pakistan,are the leading traders of Basmati rice,whe...Aromatic rice is considered an important commodity in the global market because of its strong aroma and eating and cooking quality.Asian countries,such as India and Pakistan,are the leading traders of Basmati rice,whereas Thailand is the major supplier of Jasmine rice in the international market.The strong aroma of rice is associated with more than 300 volatile compounds,among which 2-acetyl-1-pyrroline(2-AP)is the principal component.2-AP is a phenotypic expression of spontaneous mutations in the recessive gene OsBadh2 or Badh2.The present review focuses on the origin,evolution and diversity of genetic resources of aromatic rice available worldwide.A brief discussion is presented on the genes responsible for quality traits along with details of their molecular genetics.This compilation and discussion will be useful for future breeding programs and the biofortification of quality traits of aromatic rice to ensure food security and nutritional need.展开更多
Polyamines （PA）, polyamine oxidases, copper amine oxidases, and nitric oxide （NO） play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxi...Polyamines （PA）, polyamine oxidases, copper amine oxidases, and nitric oxide （NO） play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxidases and copper amine oxidases may explain in part PA-mediated responses. Involvement of a copper amine oxidase gene, COPPER AMINE OXIDASEI （CuAO1）, of Arabidopsis was tested for its role in stress responses using the knockouts cuao1-1 and cuaol-2. PA-induced and ABA-induced NO production investigated bY fluorometry and fluorescence microscopy showed that the cuaol-1 and cuaol-2 are impaired in NO production, suggesting a function of CuAO1 in PA and ABA-mediated NO production. Furthermore, we found a PA-dependent increase in protein S-nitrosylation. The addition of PA and ABA also resulted in H2O2 increases, cuao1-1 and cuao1-2 showed less sensitivity to exogenous ABA supplementation during germination, seedling establishment, and root growth inhibition as compared to wild-type. In response to ABA treatment, expression levels of the stress-responsive genes RD29A and ADH1 were significantly lower in the knockouts. These observations characterize cuao1-1 and cuao1-2 as ABA-insensitive mutants. Taken together, our findings extend the ABA signal transduction network to include CuAO1 as one potential contributor to enhanced NO production by ABA.展开更多
Background The critical roles of polyamines in cell growth and differentiation have made polyamJne metabolic pathway a promising target for antitumor therapy. Recent studies have demonstrated in vitro that some antitu...Background The critical roles of polyamines in cell growth and differentiation have made polyamJne metabolic pathway a promising target for antitumor therapy. Recent studies have demonstrated in vitro that some antitumor polyamine analogues could be used as substrates and oxidized by purified recombinant human N^1-acetylpolyamine oxidase （APAO, an enzyme that catabolizes natural poiyamines）, indicating a potential role of APAO in determining the sensitivity of cancer cells to specific antitumor analogues. This study evaluated, in vivo, the effect of APAO on cytotoxicity of antitumor polyamine analogue, N^1-cyclopropylmethyl-N^11-ethylnorspermine （CPENS） and its mechanism when highly expressed in human lung cancer line A549. Methods A clone with high expression of APAO was obtained by transfecting A549 lung cancer ceil line with pcDNA3.1/APAO plasmid and selecting with quantitative realtime PCR and APAO activity assay. Cell proliferation was determined by MTT method and apoptosis related events were evaluated by DNA fragmentation, sub-G1/flow cytometric assay, western blotting （for cytochrome C and Bax） and colorimetric assay （for casapse-3 activity）. Results A clone highly expressing APAO was obtained. High expression of APAO in A549 cells inhibited accumulation of CPENS, decreased their sensitivity to the toxicity of CPENS and prevented CPENS induced apoptosis. Conclusion These results indicate a new drug resisting, mechanism in the tumor cells. High expression of APAO can greatly decrease the sensitivity of tumor cells to the specific polyamine analogues by detoxifying those analogues and prevent analogue induced apoptosis.展开更多
基金This work was supported by the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20140483)China Postdoctoral Science Foundation(Grant No.2014M560451).
文摘Peach(Prunus persica Batsch‘Yuhualu’)fruit are sensitive to chilling injury(CI).Proline,polyamine(PA),and nitric oxide(NO)are important small regulators of various metabolic pathways under chilling stress that mitigate CI.Ethylene is known to promote senescence and CI,while 1-methylcyclopropene(1-MCP)is an antagonist that inhibits the effects of ethylene.However,how1-MCP and ethylene affect proline,PA,and NO levels under chilling stress remains unclear.To address these questions,1-MCP(1μL·L^(−1))and ethylene(1μL·L^(−1))treatments were applied to peach fruit.Fruit were stored at 4°C for 28 d,then moved to 25°C for 3 d immediately after cold storage.Peach fruit exhibited CI symptoms after 7 d of cold storage with enhanced electrolyte leakage and malondialdehyde contents.The 1-MCP treatment significantly(P<0.05)restrained peach CI,and fruit did not exhibit CI symptoms until 14 d of cold storage.Proline and PAs in peach under chilling stress weremostly synthesized from glutamate and arginine,which were catalyzed by1-pyrroline-5-carboxylate synthetase and arginine decarboxylase,respectively.1-MCPtreated fruit exhibited higher proline and PA contents and enhanced chilling tolerance compared to the control,while ethylene-treated fruit had lower proline and PA contents and reduced chilling tolerance.Ethylene-treated fruit,which exhibited more severe CI symptoms compared to the control,had significantly(P<0.05)lower NO contents and NO synthase activities.However,NOmay not be a direct acting factor in 1-MCPinduced chilling tolerance,as 1-MCP-treated fruit had lower NO contents and NO synthase activities compared to the control.In conclusion,proline and PA clearly played direct and important roles in 1-MCP-induced peach chilling tolerance,while NO may not be actively involved.
基金supported by the National Basic Research Program of China(973 project:No.2004CB518908)the National Natural Science Foundation of China(No.30472093)to SLthe 0utstanding 0verseas Chinese Scholars Fund of Chinese Academy of Sciences(No.2005-2-6)to S.J.
文摘A series of novel aromatic-linked polyamine macrocyclic derivatives have been synthesized. Their structures were confirmed by MS and ^1H NMR. These compounds exhibited potent anti-HIV-1 activities.
文摘<abstract>Aim: To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis. Methods: Male golden hamsters of 7-week-old were kept under a light and dark cycle of 14 h and 10 h for 1 week to stimulate maximally the gonadal function. DES was injected subcutaneously at doses of 0.01 mg·kg-1·day-1, 0.1 mg·kg-1·day-1 and 1 mg·kg-1·day-1 for one week. Results: DES treatment caused a significant decrease in the weight of epididymis. The activity of epididymal ornithine decar boxylase (ODC) increased 1 day after DES treatment, kept at a high level for 4 days and then decreased to nearly normal level at day 7. The activity of spermidine/spermine N1-acetyltransferase (SSAT) also increased transiently after DES treatment. The contents of putrescine, spermidine, spermine and N1-acetylspermidine were increased 1 day -4 days after DES treatment and restored to normal at day 7. All these changes showed a marked difference between the caput and the cauda. Conclusion: The polyamine biosynthesis in the hamster epididymis can be affected by DES, a xenoestrogen. DES may probably affect polyamine metabolism in the epididymis by regulating the rate-limiting enzymes involved in the polyamine biosynthesis.
基金Supported by The National 863 Program, Nos. SQ2009AA02-XK1482570 and 2006AA02A402Beijing Municipal Committee of Science and Technology, No. D0905001040631Beijing Capital Development Foundation of Health Bureau, No.2007-2051
文摘AIM: To investigate the expression of myofibrillogenesis regulator-1 (MR-1) in relation to clinicopathological parameters and postoperative survival in a group of Chinese patients with gastric cancer. METHODS: In our previous study of human wholegenome gene expression profiling, the differentially expressed genes were detected in the gastric cancer and its adjacent noncancerous mucosa. We found that MR-1 was associated with the location and differentiation of tumors. In this study, MR-1 protein expression was determined by immunohistochemistry in specimens of primary cancer and the adjacent noncancerous tissues from gastric cancer patients. A set of real-time quantitative polymerase chain reaction assays based on the Universal ProbeLibrary-a collection of 165 presynthesized, fluorescence-labeled locked nucleic acid hydrolysis probes-was designed specifically to detect the expression of MR-1 mRNA. The correlation was analyzed between the expression of MR-1 and other tumor characteristics which may influence the prognosis of gastric cancer patients. A retrospective cohort study on the prognosis was carried out and clinical data were collected from medical records. RESULTS: MR-1 mRNA and protein could be detected in gastric cancer tissues as well as in matched noncancerous tissues. MR-1 was up-regulated at both mRNA (5.459 ± 0.639 vs 1.233 ± 0.238, P < 0.001) and protein levels (34.2% vs 13.2%, P = 0.003) in gastric cancer tissues. Correlation analysis demonstrated that high expression of MR-1 in gastric cancer was significantly correlated with clinical stage (P = 0.034). Kaplan-Meier analysis showed that the postoperative survival of the MR-1 positive group tended to be poorer than that of the MR-1 negative group, and the difference was statistically significant (P = 0.002). Among all the patients with stageⅠ-Ⅳ carcinoma, the 5-year survival rates of MR-1 positive and negative groups were 50.40% and 12.70%, respectively, with respective median survival times of 64.27 mo (95%CI: 13.41-115.13) and 16.77 mo (95%CI: 8.80-24.74). Univariate and multivariate analyses were performed to compare the impact of MR-1 expression and other clinicopathological parameters on prognosis. In a univariate analysis on all 70 specimens, 6 factors were found to be significantly associated with the overall survival statistically: including MR-1 expression, depth of invasion, distant metastasis, lymph node metastasis, vascular invasion and the tumor node metastasis (TNM) stage based on the 7th edition of the International Union against Cancer TNM classification. To avoid the influence caused by univariate analysis, the expressions of MR-1 as well as other parameters were examined in multivariate Cox analysis. Clinicopathological variables that might affect the prognosis of gastric cancer patients were analyzed by Cox regression analysis, which showed that MR-1 expression and TNM stage were independent predictors of postoperative survival. The best mathematical multivariate Cox regression model consisted of two factors: MR-1 expression and TNM stage. Our results indicated that MR-1 protein could act as an independent marker for patient overall survival [Hazard ratio (HR): 2.215, P = 0.043]. CONCLUSION: MR-1 is an important variable that can be used to evaluate the outcome, prognosis and targeted therapy of gastric cancer patients.
基金supported by the National Key Technology Research and Development Program of China (2018YFD1000900)the Natural Science Foundation of Shandong Province(ZR2020MC094)+1 种基金the Natural Science Foundation of Shandong Province (ZR2021QC163)Special Funds for Local Science and Technology Development Guided by the Central Committee(YDZX20203700001861)。
文摘The Ca^(2+)/CaM signal transduction pathway helps plants adapt to environmental stress. However, our knowledge on the functional proteins of C^(2+)/CaM pathway in peanut(Arachis hypogeae L.) remains limited. In the present study, a novel calmodulin 4(CaM4)-binding protein S-adenosyl-methionine synthetase 1(SAMS1) in peanut was identified using a yeast two-hybrid assay. Expression of AhSAMS1was induced by Ca^(2+), ABA, and salt stress. To elucidate the function of AhSAMS1, physiological and phenotypic analyses were performed with wild-type and transgenic materials. Overexpression of AhSAMS1increased spermidine and spermidine synthesis while decreased the contents of ethylene, thereby eliminating excessive reactive oxygen species(ROS) in transgenic lines under salt stress. AhSAMS1 reduced uptake of Na+and leakage of K+from mesophyll cells, and was less sensitive to salt stress during early seedling growth, in agreement with the induction of SOS and NHX genes Transcriptomics combined with epigenetic regulation uncovered relationships between differentially expressed genes and differentially methylated regions, which raised the salt tolerance and plants growth. Our findings support a model in which the role of AhSAMS1 in the ROS-dependent regulation of ion homeostasis was enhanced by Ca^(2+)/CaM while AhSAMS1-induced methylation was regulated by CaM, thus providing a new strategy for increasing the tolerance of plants to salt stress.
基金supported by the National Natural Science Foundation of China,Nos.81501048(to JD),81801236(to ZMX),81974189(to HLT)Shanghai 6th People’s Hospital Research Fund,No.ynlc201808(to JD).
文摘Studies have found that the phosphatase actin regulatory factor 1 expression can be related to stroke,but it remains unclear whether changes in phosphatase actin regulatory factor 1 expression also play a role in traumatic brain injury.In this study we found that,in a mouse model of traumatic brain injury induced by controlled cortical impact,phosphatase actin regulatory factor 1 expression is increased in endothelial cells,neurons,astrocytes,and microglia.When we overexpressed phosphatase actin regulatory factor 1 by injection an adeno-associated virus vector into the contused area in the traumatic brain injury mice,the water content of the brain tissue increased.However,when phosphatase actin regulatory factor 1 was knocked down,the water content decreased.We also found that inhibiting phosphatase actin regulatory factor 1 expression regulated the nuclear factor kappa B signaling pathway,decreased blood-brain barrier permeability,reduced aquaporin 4 and intercellular adhesion molecule 1 expression,inhibited neuroinflammation,and neuronal apoptosis,thereby improving neurological function.The findings from this study indicate that phosphatase actin regulatory factor 1 may be a potential therapeutic target for traumatic brain injury.
基金University Grant Commission, New Delhi, India for providing Non-National Eligibility Test fellowship
文摘Aromatic rice is considered an important commodity in the global market because of its strong aroma and eating and cooking quality.Asian countries,such as India and Pakistan,are the leading traders of Basmati rice,whereas Thailand is the major supplier of Jasmine rice in the international market.The strong aroma of rice is associated with more than 300 volatile compounds,among which 2-acetyl-1-pyrroline(2-AP)is the principal component.2-AP is a phenotypic expression of spontaneous mutations in the recessive gene OsBadh2 or Badh2.The present review focuses on the origin,evolution and diversity of genetic resources of aromatic rice available worldwide.A brief discussion is presented on the genes responsible for quality traits along with details of their molecular genetics.This compilation and discussion will be useful for future breeding programs and the biofortification of quality traits of aromatic rice to ensure food security and nutritional need.
文摘Polyamines （PA）, polyamine oxidases, copper amine oxidases, and nitric oxide （NO） play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxidases and copper amine oxidases may explain in part PA-mediated responses. Involvement of a copper amine oxidase gene, COPPER AMINE OXIDASEI （CuAO1）, of Arabidopsis was tested for its role in stress responses using the knockouts cuao1-1 and cuaol-2. PA-induced and ABA-induced NO production investigated bY fluorometry and fluorescence microscopy showed that the cuaol-1 and cuaol-2 are impaired in NO production, suggesting a function of CuAO1 in PA and ABA-mediated NO production. Furthermore, we found a PA-dependent increase in protein S-nitrosylation. The addition of PA and ABA also resulted in H2O2 increases, cuao1-1 and cuao1-2 showed less sensitivity to exogenous ABA supplementation during germination, seedling establishment, and root growth inhibition as compared to wild-type. In response to ABA treatment, expression levels of the stress-responsive genes RD29A and ADH1 were significantly lower in the knockouts. These observations characterize cuao1-1 and cuao1-2 as ABA-insensitive mutants. Taken together, our findings extend the ABA signal transduction network to include CuAO1 as one potential contributor to enhanced NO production by ABA.
基金This work was supported by grants from the National Natural Science Foundation of China （No. 30772590） and Natural Science Foundation of Hubei Department of Education （No. D200713003）.
文摘Background The critical roles of polyamines in cell growth and differentiation have made polyamJne metabolic pathway a promising target for antitumor therapy. Recent studies have demonstrated in vitro that some antitumor polyamine analogues could be used as substrates and oxidized by purified recombinant human N^1-acetylpolyamine oxidase （APAO, an enzyme that catabolizes natural poiyamines）, indicating a potential role of APAO in determining the sensitivity of cancer cells to specific antitumor analogues. This study evaluated, in vivo, the effect of APAO on cytotoxicity of antitumor polyamine analogue, N^1-cyclopropylmethyl-N^11-ethylnorspermine （CPENS） and its mechanism when highly expressed in human lung cancer line A549. Methods A clone with high expression of APAO was obtained by transfecting A549 lung cancer ceil line with pcDNA3.1/APAO plasmid and selecting with quantitative realtime PCR and APAO activity assay. Cell proliferation was determined by MTT method and apoptosis related events were evaluated by DNA fragmentation, sub-G1/flow cytometric assay, western blotting （for cytochrome C and Bax） and colorimetric assay （for casapse-3 activity）. Results A clone highly expressing APAO was obtained. High expression of APAO in A549 cells inhibited accumulation of CPENS, decreased their sensitivity to the toxicity of CPENS and prevented CPENS induced apoptosis. Conclusion These results indicate a new drug resisting, mechanism in the tumor cells. High expression of APAO can greatly decrease the sensitivity of tumor cells to the specific polyamine analogues by detoxifying those analogues and prevent analogue induced apoptosis.
