Three rice varieties, Zhonghan 3, Shanyou 63 and Aizizhan, were used as materials in detecting differential active methyl cycle and transfer related gene expression in response to drought stress. The experiment was pe...Three rice varieties, Zhonghan 3, Shanyou 63 and Aizizhan, were used as materials in detecting differential active methyl cycle and transfer related gene expression in response to drought stress. The experiment was performed by gene chip and mRNA differential display technologies under the conditions of drought simulated with 10% PEG6000 solution. The results indicated that the methyl cycle could be activated in the leaves of Zhonghan 3 and Shanyou 63 but inhibited in the leaves of Aizizhan under drought stress. Furthermore, drought stress could induce the expression of a large number of methyltransferase genes, especially the transcription of Rubisco protein methylation related genes, which are beneficial for prevention of Rubisco protein oxidation and degradation, and drought stress could inhibit the transcription of DNA methyltransferase genes and histone methyltransferase genes. This result confirmed that the active methyl cycle and transfer related genes were involved in rice drought resistance.展开更多
Background To investigate the effects of DNA methylation on the expression of tumor-associated genes and the cell cycle in human gastric cancer cells. Methods Two gastric cancer cell lines (MKN-45 and HGC-27) we...Background To investigate the effects of DNA methylation on the expression of tumor-associated genes and the cell cycle in human gastric cancer cells. Methods Two gastric cancer cell lines (MKN-45 and HGC-27) were treated with DNA methyltransferase (DNMT) inhibitor,5-aza-2’-deoxycytidine (5-aza-dC). The expressions of p16 INK4A,p21 WAF1,p53 , p73 ,c-Ha-ras and c-myc genes mRNA were detected by using reverse transcription PCR (RT-PCR). DNA methylation status of p16 INK4A gene promoter was assayed by bisulfite modification and sequencing. The cell cycle was analyzed by using flow cytometry (FCM). Results 5-aza-dC induced the demethylation of p16 INK4A gene promoter. The expression of p16 INK4A mRNA was obviously up-regulated by treatment with 10 μmol/L (MKN-45 cells) or 5 μmol/L (HGC-27 cells) of 5-aza-dC for 24 hours. However,5-aza-dC treatment failed to regulate the expressions of p21 WAF1,p53 , p73 ,c-Ha-ras and c-myc genes in MKN-45 and HGC-27 cells. Furthermore,5-aza-dC induced the cell cycle arrest in G1 phase in HGC-27 cell,but not in MKN-45 cell. Conclusions DNA methylation regulates the transcription of p16 INK4A but not p21 WAF1 and proto-oncogenes in human gastric cancer cell lines MKN-45 and HGC-27.展开更多
基金supported by the Open Research Fund Program of Jiangsu Key Laboratory of Crop Cultivation and Physiology,China (Grant No.0273880036)
文摘Three rice varieties, Zhonghan 3, Shanyou 63 and Aizizhan, were used as materials in detecting differential active methyl cycle and transfer related gene expression in response to drought stress. The experiment was performed by gene chip and mRNA differential display technologies under the conditions of drought simulated with 10% PEG6000 solution. The results indicated that the methyl cycle could be activated in the leaves of Zhonghan 3 and Shanyou 63 but inhibited in the leaves of Aizizhan under drought stress. Furthermore, drought stress could induce the expression of a large number of methyltransferase genes, especially the transcription of Rubisco protein methylation related genes, which are beneficial for prevention of Rubisco protein oxidation and degradation, and drought stress could inhibit the transcription of DNA methyltransferase genes and histone methyltransferase genes. This result confirmed that the active methyl cycle and transfer related genes were involved in rice drought resistance.
基金ThisworkwassupportedinpartbytheNationalNaturalScienceFoundationofChina (No 3 0 170 413 ) ,theFoundationfortheAuthorofNationalExcellentDoctoralDissertationofP .R .China (No 199946)andtheKeySubjectFundsofShanghaiEducationCommittee
文摘Background To investigate the effects of DNA methylation on the expression of tumor-associated genes and the cell cycle in human gastric cancer cells. Methods Two gastric cancer cell lines (MKN-45 and HGC-27) were treated with DNA methyltransferase (DNMT) inhibitor,5-aza-2’-deoxycytidine (5-aza-dC). The expressions of p16 INK4A,p21 WAF1,p53 , p73 ,c-Ha-ras and c-myc genes mRNA were detected by using reverse transcription PCR (RT-PCR). DNA methylation status of p16 INK4A gene promoter was assayed by bisulfite modification and sequencing. The cell cycle was analyzed by using flow cytometry (FCM). Results 5-aza-dC induced the demethylation of p16 INK4A gene promoter. The expression of p16 INK4A mRNA was obviously up-regulated by treatment with 10 μmol/L (MKN-45 cells) or 5 μmol/L (HGC-27 cells) of 5-aza-dC for 24 hours. However,5-aza-dC treatment failed to regulate the expressions of p21 WAF1,p53 , p73 ,c-Ha-ras and c-myc genes in MKN-45 and HGC-27 cells. Furthermore,5-aza-dC induced the cell cycle arrest in G1 phase in HGC-27 cell,but not in MKN-45 cell. Conclusions DNA methylation regulates the transcription of p16 INK4A but not p21 WAF1 and proto-oncogenes in human gastric cancer cell lines MKN-45 and HGC-27.
