Induction and mobilization of transposable elements （TEs） following DNA damage or other stresses has been reported in prokaryotes and eukaryotes. Recently it was discovered that eukaryotic TEs are frequently associa...Induction and mobilization of transposable elements （TEs） following DNA damage or other stresses has been reported in prokaryotes and eukaryotes. Recently it was discovered that eukaryotic TEs are frequently associated with long non-coding RNAs （IncRNAs）, many of which are also upregulated by stress. Yet, it is unknown whether DNA damage-induced transcriptional activation of TEs and IncRNAs occurs sporadically or is a synchronized, genome-wide response. Here we investigated the transcriptome of Arabidopsis wild- type （WT） and ataxia telangiectasia mutated （atm） mutant plants 3 h after induction of DNA damage. In WT, expression of 5.2% of the protein-coding genes is 〉 2-fold changed, whereas in atm plants, only 2.6% of these genes are regulated, and the response of genes associated with DNA repair, replication, and cell cy- cle is largely lost. In contrast, only less than 0.6% of TEs and IncRNAs respond to DNA damage in WT plants, and the regulation of 〉95% of them is ATM-dependent. The ATM-downstream factors BRCA1, DRM1, JMJ30, AGO2, and the ATM-independent AGO4 participate in the regulation of individual TEs and IncRNAs. Remarkably, protein-coding genes located adjacent to DNA damage-responsive TEs and IncRNAs are frequently coexpressed, which is consistent with the hypothesis that TEs and IncRNAs located close to genes commonly function as controlling elements.展开更多
目的:探讨长链非编码RNA(long non-coding RNA,lncRNA)DNA损伤激活的非编码RNA(non-coding RNA-activated by DNA damage,NORAD)对食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)细胞株EC9706增殖和迁移能力的影响及其机制...目的:探讨长链非编码RNA(long non-coding RNA,lncRNA)DNA损伤激活的非编码RNA(non-coding RNA-activated by DNA damage,NORAD)对食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)细胞株EC9706增殖和迁移能力的影响及其机制。方法:采用RT-PCR法检测不同ESCC细胞(EC9706、TE1、YES-2、KYSE150)中NORAD m RNA表达水平,通过RNA干扰技术将NORAD的小干扰RNA(siRNA)转染到EC9706细胞(si-NORAD组)以建立NORAD低表达细胞,另设置空白对照组(Ctrl组,不转染任何序列)及阴性对照组(NC组,转染siRNA阴性对照序列),qPCR验证其转染效果。用MTT、平板克隆形成和划痕愈合实验检测敲低NORAD前后EC9706细胞增殖和迁移能力的变化,Western blotting检测敲低NORAD前后EC9706细胞中上皮钙黏蛋白(E-cadherin)、神经钙黏蛋白(N-cadherin)和锌指转录因子Snail的表达变化。结果:在4种ESCC细胞中NORAD mRNA均呈高表达状态,同时与TE1、YES-2、KYSE150细胞相比,EC9706细胞中NORAD mRNA呈显著高表达(P<0.01)。与Ctrl组和NC组比较,转染NORAD-siRNA后,si-NORAD组EC9706细胞中NORAD表达水平显著降低(均P<0.01),EC9706细胞的增殖和迁移能力显著降低(均P<0.05);敲低NORAD表达后,EC9706细胞中E-cadherin表达升高而N-cadherin和Snail表达降低(均P<0.05)。结论:NORAD在EC9706细胞中呈高表达状态,敲低NORAD表达可通过上调E-cadherin、下调N-cadherin和Snail表达而抑制EC9706细胞的增殖和迁移能力。展开更多
RNA can catalyze and participate in many chemical and biochemical reactions. Non-coding RNAs （ncRNA） can regulate cellular transcription and translation reactions. We have demonstrated biochemically that RNA can als...RNA can catalyze and participate in many chemical and biochemical reactions. Non-coding RNAs （ncRNA） can regulate cellular transcription and translation reactions. We have demonstrated biochemically that RNA can also interfere with DNA polymerization via transforming DNA polymerase into deoxyribonucleoside triphosphate diphosphatase （dNTP-DPase）. RNA, even with six nucleotides, can transform DNA polymerase into dNTP-DPase, and the dNTP-DPase activity causes the hydrolysis of dNTPs into dNMPs and pyrophosphate. Moreover, we have found that DNA polymerases from several families generally have similar RNA-dependent dNTP-DPase activity. We have also observed that in the presence of RNA, when the dNTP concentrations are relatively low, and that the dNTP-DPase activity can deplete dNTPs and interfere with DNA polymerization Thus, we have discovered for the first time that in the presence of RNA, DNA polymerase can behave as a diphosphatase and inhibit DNA synthesis when dNTP quantity is low. These in vitro observations might imply a plausible role of RNA in vivo, such as suppressing DNA synthesis during a resting phase （Go） of the cell cycle, when RNA quantity is high and dNTP quantity is low.展开更多
文摘Induction and mobilization of transposable elements （TEs） following DNA damage or other stresses has been reported in prokaryotes and eukaryotes. Recently it was discovered that eukaryotic TEs are frequently associated with long non-coding RNAs （IncRNAs）, many of which are also upregulated by stress. Yet, it is unknown whether DNA damage-induced transcriptional activation of TEs and IncRNAs occurs sporadically or is a synchronized, genome-wide response. Here we investigated the transcriptome of Arabidopsis wild- type （WT） and ataxia telangiectasia mutated （atm） mutant plants 3 h after induction of DNA damage. In WT, expression of 5.2% of the protein-coding genes is 〉 2-fold changed, whereas in atm plants, only 2.6% of these genes are regulated, and the response of genes associated with DNA repair, replication, and cell cy- cle is largely lost. In contrast, only less than 0.6% of TEs and IncRNAs respond to DNA damage in WT plants, and the regulation of 〉95% of them is ATM-dependent. The ATM-downstream factors BRCA1, DRM1, JMJ30, AGO2, and the ATM-independent AGO4 participate in the regulation of individual TEs and IncRNAs. Remarkably, protein-coding genes located adjacent to DNA damage-responsive TEs and IncRNAs are frequently coexpressed, which is consistent with the hypothesis that TEs and IncRNAs located close to genes commonly function as controlling elements.
文摘目的:探讨长链非编码RNA(long non-coding RNA,lncRNA)DNA损伤激活的非编码RNA(non-coding RNA-activated by DNA damage,NORAD)对食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)细胞株EC9706增殖和迁移能力的影响及其机制。方法:采用RT-PCR法检测不同ESCC细胞(EC9706、TE1、YES-2、KYSE150)中NORAD m RNA表达水平,通过RNA干扰技术将NORAD的小干扰RNA(siRNA)转染到EC9706细胞(si-NORAD组)以建立NORAD低表达细胞,另设置空白对照组(Ctrl组,不转染任何序列)及阴性对照组(NC组,转染siRNA阴性对照序列),qPCR验证其转染效果。用MTT、平板克隆形成和划痕愈合实验检测敲低NORAD前后EC9706细胞增殖和迁移能力的变化,Western blotting检测敲低NORAD前后EC9706细胞中上皮钙黏蛋白(E-cadherin)、神经钙黏蛋白(N-cadherin)和锌指转录因子Snail的表达变化。结果:在4种ESCC细胞中NORAD mRNA均呈高表达状态,同时与TE1、YES-2、KYSE150细胞相比,EC9706细胞中NORAD mRNA呈显著高表达(P<0.01)。与Ctrl组和NC组比较,转染NORAD-siRNA后,si-NORAD组EC9706细胞中NORAD表达水平显著降低(均P<0.01),EC9706细胞的增殖和迁移能力显著降低(均P<0.05);敲低NORAD表达后,EC9706细胞中E-cadherin表达升高而N-cadherin和Snail表达降低(均P<0.05)。结论:NORAD在EC9706细胞中呈高表达状态,敲低NORAD表达可通过上调E-cadherin、下调N-cadherin和Snail表达而抑制EC9706细胞的增殖和迁移能力。
基金financially supported by the Georgia Cancer Coalition(GCC)Distinguished Cancer Clinicians and Scientists,USA NSF(IIP-1340153)and NIH(R01GM095881)
文摘RNA can catalyze and participate in many chemical and biochemical reactions. Non-coding RNAs （ncRNA） can regulate cellular transcription and translation reactions. We have demonstrated biochemically that RNA can also interfere with DNA polymerization via transforming DNA polymerase into deoxyribonucleoside triphosphate diphosphatase （dNTP-DPase）. RNA, even with six nucleotides, can transform DNA polymerase into dNTP-DPase, and the dNTP-DPase activity causes the hydrolysis of dNTPs into dNMPs and pyrophosphate. Moreover, we have found that DNA polymerases from several families generally have similar RNA-dependent dNTP-DPase activity. We have also observed that in the presence of RNA, when the dNTP concentrations are relatively low, and that the dNTP-DPase activity can deplete dNTPs and interfere with DNA polymerization Thus, we have discovered for the first time that in the presence of RNA, DNA polymerase can behave as a diphosphatase and inhibit DNA synthesis when dNTP quantity is low. These in vitro observations might imply a plausible role of RNA in vivo, such as suppressing DNA synthesis during a resting phase （Go） of the cell cycle, when RNA quantity is high and dNTP quantity is low.
