Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/ reperfusion area, and decrea...Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/ reperfusion area, and decrease the number of apoptotic neurons. However, the anti-apoptotic mechanism of Ku70 remains unclear. In this study, fastigial nucleus stimulation was given to rats 24, 48, and 72 hours before cerebral ischemia/reperfusion injury. Results from the electrical stim- ulation group revealed that rats exhibited a reduction in brain infarct size, a significant increase in the expression of KuT0 in cerebral ischemia/reperfusion regions, and a decreased number of terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL）-positive cells. Double immunofluorescence staining revealed no co-localization of Ku70 with TUNEL-positive cells. However, Ku70 partly co-localized with Bax protein in the cytoplasm of rats with cerebral ischemia/reperfusion injury. These findings suggest an involvement of Ku70 with Bax in the cy- toplasm of rats exposed to electrical stimulation of the cerebellar fastigial nucleus, and may thus provide an understanding into the anti-apoptotic activity of KuT0 in cerebral ischemia/reperfu- sion injury.展开更多
目的探讨不同期别乳腺癌组织中DNA依赖蛋白激酶(DNA dependent protein kinase,DNA-PK)的两个调节亚单位Ku70、Ku80的表达变化情况.方法采用免疫组化SP法检测Ⅰ～Ⅳ期乳腺癌组织各30例中的Ku70、Ku80的表达情况.结果Ku70、Ku80在Ⅰ期乳...目的探讨不同期别乳腺癌组织中DNA依赖蛋白激酶(DNA dependent protein kinase,DNA-PK)的两个调节亚单位Ku70、Ku80的表达变化情况.方法采用免疫组化SP法检测Ⅰ～Ⅳ期乳腺癌组织各30例中的Ku70、Ku80的表达情况.结果Ku70、Ku80在Ⅰ期乳腺癌组织中呈高表达,在Ⅱ期中的表达有降低趋势(与Ⅰ期比较P<0.01,与Ⅲ期比较P>0.05,与Ⅳ期比较P<0.01),在Ⅲ、Ⅳ期乳腺癌组织中的表达明显低于Ⅰ期乳腺癌(P<0.01;P<0.01).结论Ku70、Ku80在不同阶段乳腺癌中的表达情况是随着乳腺癌的分期变化而变化,从早期、中期到晚期呈逐渐降低趋势,可能与乳腺癌的分期及预后有一定相关性.展开更多
BACKGROUND： Numerous studies have shown that apoptosis, caused by cerebral ischemia/reperfusion injury, is a dynamic evolving process that occurs in a time-dependent fashion. Non-apoptotic cells can result in apoptos...BACKGROUND： Numerous studies have shown that apoptosis, caused by cerebral ischemia/reperfusion injury, is a dynamic evolving process that occurs in a time-dependent fashion. Non-apoptotic cells can result in apoptosis, with a prolonged reperfusion period and an accumulation of DNA damage. Recent studies have indicated that theanine has a protective effect on the brain. Nonetheless, there is no research relating to whether theanine is neuroprotective following brain injury. OBJECTIVE： To investigate the effects of theanine on apoptosis in the cerebral cortex and mRNA expression of the DNA repair protein, XRCC1, and DNA repair enzyme, Ku70, at various time points following global cerebral ischemia/reperfusion in rats. DESIGN, TIME AND SETTING： A randomized, controlled animal study was performed at the Pharmacological Laboratory of Animal Experimental Center of Xi＇an Jiaotong University, China, from April to October 2007. MATERIALS： Theanine （Wuhan Remote Technology Co., Ltd., China）, XRCC1, Ku70 and GAPDH primers （Shanghai Sangon Biological Engineering Technology ＆ Services Co., Ltd., China） were used in this study. METHODS： A total of 108 healthy, male Sprague Dawley rats were randomly divided into sham operation, ischemia/reperfusion and theanine groups. Each group was further divided into 6 subgroups, with six rats in each, according to reperfusion time （2, 6, 12, 24, 48 and 72 hours）. Rat models of global cerebral ischemia/reperfusion were established by the four-vessel occlusion method. Theanine （1 000 mg/kg） was injected into the caudal vein of rats in the theanine group immediately after surgery. Saline （4 mL/kg） was used in the sham operation and ischemia/reperfusion groups. The same dose was administered every 24 hours. MAIN OUTCOME MEASURES： Flow cytometry was employed to determine apoptosis of cerebral cortical neurons. Real-time reverse transcdption-polymerase chain reaction was applied to quantify the expression of XRCC1 and Ku70 mRNA in the cerebral cortex. RESULTS展开更多
Histone H3 Lys36(H3K36)methylation and its associated modifiers are crucial for DNA double-strand break(DSB)repair,but the mechanism governing whether and how different H3K36 methylation forms impact repair pathways i...Histone H3 Lys36(H3K36)methylation and its associated modifiers are crucial for DNA double-strand break(DSB)repair,but the mechanism governing whether and how different H3K36 methylation forms impact repair pathways is unclear.Here,we unveil the distinct roles of H3K36 dimethylation(H3K36me2)and H3K36 trimethylation(H3K36me3)in DSB repair via non-homologous end joining(NHEJ)or homologous recombination(HR).Yeast cells lacking H3K36me2 or H3K36me3 exhibit reduced NHEJ or HR efficiency.y Ku70 and Rfa1 bind H3K36me2-or H3K36me3-modified peptides and chromatin,respectively.Disrupting these interactions impairs y Ku70 and Rfa1 recruitment to damaged H3K36me2-or H3K36me3-rich loci,increasing DNA damage sensitivity and decreasing repair efficiency.Conversely,H3K36me2-enriched intergenic regions and H3K36me3-enriched gene bodies independently recruit y Ku70 or Rfa1 under DSB stress.Importantly,human KU70 and RPA1,the homologs of y Ku70 and Rfa1,exclusively associate with H3K36me2 and H3K36me3 in a conserved manner.These findings provide valuable insights into how H3K36me2 and H3K36me3 regulate distinct DSB repair pathways,highlighting H3K36 methylation as a critical element in the choice of DSB repair pathway.展开更多
Non-homologous end-joining(NHEJ) is a predominant pathway for the repair of DNA double-strand breaks(DSB). It inhibits the efficiency of homologous recombination(HR) by competing for DSB targets. To improve the effici...Non-homologous end-joining(NHEJ) is a predominant pathway for the repair of DNA double-strand breaks(DSB). It inhibits the efficiency of homologous recombination(HR) by competing for DSB targets. To improve the efficiency of HR, multiple CRISPR interference(CRISPRi) and Natronobacterium gregoryi Argonaute(NgAgo) interference(NgAgoi) systems have been designed for the knockdown of NHEJ key molecules, KU70, KU80, polynucleotide kinase/phosphatase(PNKP), DNA ligase IV(LIG4), and NHEJ1. Suppression of KU70 and KU80 by CRISPRi dramatically promoted(P<0.05) the efficiency of HR to 1.85-and 1.58-fold, respectively, whereas knockdown of PNKP, LIG4, and NHEJ1 repair factors did not significantly increase(P>0.05) HR efficiency. Interestingly, although the NgAgoi system significantly suppressed(P<0.05) KU70, KU80, PNKP, LIG4, and NHEJ1 expression, it did not improve(P>0.05) HR efficiency in primary fetal fibroblasts. Our result showed that both NgAgo and catalytically inactive Cas9(dCas9) could interfere with the expression of target genes, but the downstream factors appear to be more active following CRISPR-mediated interference than that of NgAgo.展开更多
基金supported by the National Natural Science Foundation of China,No.30860291
文摘Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/ reperfusion area, and decrease the number of apoptotic neurons. However, the anti-apoptotic mechanism of Ku70 remains unclear. In this study, fastigial nucleus stimulation was given to rats 24, 48, and 72 hours before cerebral ischemia/reperfusion injury. Results from the electrical stim- ulation group revealed that rats exhibited a reduction in brain infarct size, a significant increase in the expression of KuT0 in cerebral ischemia/reperfusion regions, and a decreased number of terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL）-positive cells. Double immunofluorescence staining revealed no co-localization of Ku70 with TUNEL-positive cells. However, Ku70 partly co-localized with Bax protein in the cytoplasm of rats with cerebral ischemia/reperfusion injury. These findings suggest an involvement of Ku70 with Bax in the cy- toplasm of rats exposed to electrical stimulation of the cerebellar fastigial nucleus, and may thus provide an understanding into the anti-apoptotic activity of KuT0 in cerebral ischemia/reperfu- sion injury.
文摘目的探讨不同期别乳腺癌组织中DNA依赖蛋白激酶(DNA dependent protein kinase,DNA-PK)的两个调节亚单位Ku70、Ku80的表达变化情况.方法采用免疫组化SP法检测Ⅰ～Ⅳ期乳腺癌组织各30例中的Ku70、Ku80的表达情况.结果Ku70、Ku80在Ⅰ期乳腺癌组织中呈高表达,在Ⅱ期中的表达有降低趋势(与Ⅰ期比较P<0.01,与Ⅲ期比较P>0.05,与Ⅳ期比较P<0.01),在Ⅲ、Ⅳ期乳腺癌组织中的表达明显低于Ⅰ期乳腺癌(P<0.01;P<0.01).结论Ku70、Ku80在不同阶段乳腺癌中的表达情况是随着乳腺癌的分期变化而变化,从早期、中期到晚期呈逐渐降低趋势,可能与乳腺癌的分期及预后有一定相关性.
基金国家自然科学基金项目(81272888)；北京市科学技术委员会重点项目( D131100005313009)Fund programNatural Science Foundation of China，Key Project of Beijing Municipal Sci-ence and Technology Commission
基金the National Natural Science Foundation of China, No. 30571790
文摘BACKGROUND： Numerous studies have shown that apoptosis, caused by cerebral ischemia/reperfusion injury, is a dynamic evolving process that occurs in a time-dependent fashion. Non-apoptotic cells can result in apoptosis, with a prolonged reperfusion period and an accumulation of DNA damage. Recent studies have indicated that theanine has a protective effect on the brain. Nonetheless, there is no research relating to whether theanine is neuroprotective following brain injury. OBJECTIVE： To investigate the effects of theanine on apoptosis in the cerebral cortex and mRNA expression of the DNA repair protein, XRCC1, and DNA repair enzyme, Ku70, at various time points following global cerebral ischemia/reperfusion in rats. DESIGN, TIME AND SETTING： A randomized, controlled animal study was performed at the Pharmacological Laboratory of Animal Experimental Center of Xi＇an Jiaotong University, China, from April to October 2007. MATERIALS： Theanine （Wuhan Remote Technology Co., Ltd., China）, XRCC1, Ku70 and GAPDH primers （Shanghai Sangon Biological Engineering Technology ＆ Services Co., Ltd., China） were used in this study. METHODS： A total of 108 healthy, male Sprague Dawley rats were randomly divided into sham operation, ischemia/reperfusion and theanine groups. Each group was further divided into 6 subgroups, with six rats in each, according to reperfusion time （2, 6, 12, 24, 48 and 72 hours）. Rat models of global cerebral ischemia/reperfusion were established by the four-vessel occlusion method. Theanine （1 000 mg/kg） was injected into the caudal vein of rats in the theanine group immediately after surgery. Saline （4 mL/kg） was used in the sham operation and ischemia/reperfusion groups. The same dose was administered every 24 hours. MAIN OUTCOME MEASURES： Flow cytometry was employed to determine apoptosis of cerebral cortical neurons. Real-time reverse transcdption-polymerase chain reaction was applied to quantify the expression of XRCC1 and Ku70 mRNA in the cerebral cortex. RESULTS
基金supported by the National Key Research and Development Program of China(2019YFA0802501)the National Natural Science Foundation of China(32270617,31971231)+1 种基金the Fundamental Research Funds for the Central Universities(2042022dx0003)the Application Fundamental Frontier Foundation of Wuhan(2020020601012225)。
文摘Histone H3 Lys36(H3K36)methylation and its associated modifiers are crucial for DNA double-strand break(DSB)repair,but the mechanism governing whether and how different H3K36 methylation forms impact repair pathways is unclear.Here,we unveil the distinct roles of H3K36 dimethylation(H3K36me2)and H3K36 trimethylation(H3K36me3)in DSB repair via non-homologous end joining(NHEJ)or homologous recombination(HR).Yeast cells lacking H3K36me2 or H3K36me3 exhibit reduced NHEJ or HR efficiency.y Ku70 and Rfa1 bind H3K36me2-or H3K36me3-modified peptides and chromatin,respectively.Disrupting these interactions impairs y Ku70 and Rfa1 recruitment to damaged H3K36me2-or H3K36me3-rich loci,increasing DNA damage sensitivity and decreasing repair efficiency.Conversely,H3K36me2-enriched intergenic regions and H3K36me3-enriched gene bodies independently recruit y Ku70 or Rfa1 under DSB stress.Importantly,human KU70 and RPA1,the homologs of y Ku70 and Rfa1,exclusively associate with H3K36me2 and H3K36me3 in a conserved manner.These findings provide valuable insights into how H3K36me2 and H3K36me3 regulate distinct DSB repair pathways,highlighting H3K36 methylation as a critical element in the choice of DSB repair pathway.
基金supported by the National Science and Technology Major Project for Breeding of New Transgenic Organisms, China (2016ZX08006002)the Guangdong Province "Flying Sail Program" Postdoctoral Foundation, China (2016)
文摘Non-homologous end-joining(NHEJ) is a predominant pathway for the repair of DNA double-strand breaks(DSB). It inhibits the efficiency of homologous recombination(HR) by competing for DSB targets. To improve the efficiency of HR, multiple CRISPR interference(CRISPRi) and Natronobacterium gregoryi Argonaute(NgAgo) interference(NgAgoi) systems have been designed for the knockdown of NHEJ key molecules, KU70, KU80, polynucleotide kinase/phosphatase(PNKP), DNA ligase IV(LIG4), and NHEJ1. Suppression of KU70 and KU80 by CRISPRi dramatically promoted(P<0.05) the efficiency of HR to 1.85-and 1.58-fold, respectively, whereas knockdown of PNKP, LIG4, and NHEJ1 repair factors did not significantly increase(P>0.05) HR efficiency. Interestingly, although the NgAgoi system significantly suppressed(P<0.05) KU70, KU80, PNKP, LIG4, and NHEJ1 expression, it did not improve(P>0.05) HR efficiency in primary fetal fibroblasts. Our result showed that both NgAgo and catalytically inactive Cas9(dCas9) could interfere with the expression of target genes, but the downstream factors appear to be more active following CRISPR-mediated interference than that of NgAgo.
