Recently, an epoch-making genome engineering technology using clustered regularly at interspaced short palindromic repeats(CRISPR) and CRISPR associated(Cas) nucleases, was developed. Previous technologies for genome ...Recently, an epoch-making genome engineering technology using clustered regularly at interspaced short palindromic repeats(CRISPR) and CRISPR associated(Cas) nucleases, was developed. Previous technologies for genome manipulation require the time-consuming design and construction of genome-engineered nucleases for each target and have, therefore, not been widely used in mouse research where standard techniques based on homologous recombination are commonly used. The CRISPR/Cas system only requires the design of sequences complementary to a target locus, making this technology fast and straightforward. In addition, CRISPR/Cas can be used to generate mice carrying mutations in multiple genes in a single step, an achievement not possible using other methods. Here, we review the uses of this technology in genetic analysis and manipulation, including achievements made possible to date and the prospects for future therapeutic applications.展开更多
拟轮枝镰孢菌(Fusarium verticillioides)是引起玉米茎基腐病和穗粒腐病的主要病原菌之一,严重威胁玉米的产量和品质。为了深入研究拟轮枝镰孢菌致病基因的功能,对该菌中非同源末端连接(non-homologous end joining,NHEJ)途径中的2个关...拟轮枝镰孢菌(Fusarium verticillioides)是引起玉米茎基腐病和穗粒腐病的主要病原菌之一,严重威胁玉米的产量和品质。为了深入研究拟轮枝镰孢菌致病基因的功能,对该菌中非同源末端连接(non-homologous end joining,NHEJ)途径中的2个关键基因FvKu70和FvKu80分别进行了基因敲除以创制高效的基因敲除菌株,并比较了野生型菌株和突变体菌株在营养生长速率、菌落形态、产孢量、对玉米的致病力和基因敲除效率等方面的差异。研究结果表明,FvKu70和FvKu80的基因缺失突变体与野生型FvLNF15-11相比,在PDA平板上的形态特征(如菌丝形态、生长速率、菌落直径、产孢量)没有明显差异,对玉米茎秆的致病力也类似。此外,选择尿嘧啶生物合成相关基因FvpyrG作为敲除的靶基因,分析了FvKu70或FvKu80缺失突变体菌株的同源重组效率,结果显示突变体菌株均显著高于野生型,其中ΔFvKu70的同源重组效率最高。综上所述,FvKu70或FvKu80基因缺失突变体可以快速又高效地实现拟轮枝镰孢菌的基因敲除,为进一步研究该菌的功能基因提供了技术支持。展开更多
目的建立含p I-SCEⅠ酶切位点的总的非同源末端连接(total non-homologous end joining,Total-NHEJ)和非经典末端连接(alternative end joining,A-EJ)修复底物的细胞株,设置特定的流式细胞术参数,定量检测依托泊苷(etoposide,VP-16)对...目的建立含p I-SCEⅠ酶切位点的总的非同源末端连接(total non-homologous end joining,Total-NHEJ)和非经典末端连接(alternative end joining,A-EJ)修复底物的细胞株,设置特定的流式细胞术参数,定量检测依托泊苷(etoposide,VP-16)对非同源末端连接(Non-homologous end joining,NHEJ)修复的影响。方法本实验通过脂质体转染含修复底物的质粒,嘌呤霉素筛选,构建起NHEJ修复系统的稳定细胞株;运用流式细胞术和PCR技术对所构建的细胞株的基因组DNA进行分析与鉴定;运用细胞免疫荧光及基因组DNA琼脂糖凝胶电泳检测VP-16诱导的DNA双链断裂(DNA double strand break,DSB)损伤,运用流式细胞术定量检测VP-16对NHEJ修复的影响。结果在所筛选的细胞中的各得到2株阳性细胞株Total-NHEJ和2株阳性细胞株A-EJ。VP-16作用浓度和时间的增加,Total-NHEJ和A-EJ修复效率增加。结论 VP-16诱导DNA损伤的同时,促进总NHEJ修复和A-EJ修复,修复呈现剂量和时间依赖性,但随着浓度和作用时间的增加,VP-16致DSB的损伤能力超过修复能力。展开更多
Hepatitis B virus(HBV)-induced hepatocellular carcinoma(HCC) is one of the most fre-quently occurring cancers.Hepadnaviral DNA integrations are considered to be essential agents which can promote the process of the he...Hepatitis B virus(HBV)-induced hepatocellular carcinoma(HCC) is one of the most fre-quently occurring cancers.Hepadnaviral DNA integrations are considered to be essential agents which can promote the process of the hepatocarcinogenesis.More and more researches were designed to find the relationship of the two.In this study,we investigated whether HBV DNA integration occurred at sites of DNA double-strand breaks(DSBs),one of the most detrimental DNA damage.An 18-bp I-SceI homing endonuclease recognition site was introduced into the DNA of HepG2 cell line by stable DNA transfection,then cells were incubated in patients’ serum with high HBV DNA copies and at the same time,DSBs were induced by transient expression of I-SceI after transfection of an I-SceI expression vector.By using nest PCR,the viral DNA was detected at the sites of the break.It appeared that integra-tion occurred between part of HBV x gene and the I-SceI induced breaks.The results suggested that DSBs,as the DNA damages,may serve as potential targets for hepadnaviral DNA insertion and the integrants would lead to widespread host genome changes necessarily.It provided a new site to investi-gate the integration.展开更多
Over the past few decades, major strides have advanced the techniques for early detection and treatment of cancer. However, metastatic tumor growth still accounts for the majority of cancer-related deaths worldwide. I...Over the past few decades, major strides have advanced the techniques for early detection and treatment of cancer. However, metastatic tumor growth still accounts for the majority of cancer-related deaths worldwide. In fact, breast cancers are notorious for relapsing years or decades after the initial clinical treatment, and this relapse can vary according to the type of breast cancer. In estrogen receptor-positive breast cancers, late tumor relapses frequently occur whereas relapses in estrogen receptor-negative cancers or triple negative tumors arise early resulting in a higher mortality risk. One of the main causes of metastasis is tumor dormancy in which cancer cells remain concealed, asymptomatic, and untraceable over a prolonged period of time. Under certain conditions, dormant cells can re-enter into the cell cycle and resume proliferation leading to recurrence. However, the molecular and cellular regulators underlying this transition remain poorly understood. To date, three mechanisms have been identified to trigger tumor dormancy including cellular, angiogenic, and immunologic dormancies. In addition, recent studies have suggested that DNA repair mechanisms may contribute to the survival of dormant cancer cells. In this article, we summarize the recent experimental and clinical evidence governing cancer dormancy. In addition, we will discuss the role of DNA repair mechanisms in promoting the survival of dormant cells. This information provides mechanistic insight to explain why recurrence occurs, and strategies that may enhance therapeutic approaches to prevent disease recurrence.展开更多
目的探究SUMO E3连接酶(zinc finger protein 451,ZNF451)介导非小细胞肺癌A549细胞和宫颈癌HeLa细胞DNA损伤修复的功能及机制。方法采用γ射线或依托泊苷处理A549细胞和HeLa细胞,CCK-8法检测细胞增殖活力,蛋白免疫印迹法检测蛋白表达量...目的探究SUMO E3连接酶(zinc finger protein 451,ZNF451)介导非小细胞肺癌A549细胞和宫颈癌HeLa细胞DNA损伤修复的功能及机制。方法采用γ射线或依托泊苷处理A549细胞和HeLa细胞,CCK-8法检测细胞增殖活力,蛋白免疫印迹法检测蛋白表达量。DR-GFP质粒系统检测DNA损伤修复水平,免疫荧光法检测蛋白的空间定位。结果依托泊苷抑制了ZNF451的表达并呈剂量及时间依赖性。30、50、80μmol/L依托泊苷处理,敲低ZNF451后的A549和HeLa细胞增殖活力显著降低(A549:t=27.62、25.61、5.32,P<0.01;HeLa:t=30.77、21.28、4.18,P<0.01)。ZNF451在DNA损伤位点处募集并与γ-H2AX存在胞内共定位和内源性的相互作用,且在30、50、80μmol/L依托泊苷处理的ZNF451敲低细胞中,γ-H2AX的表达水平显著增加(A549:t=6.12、10.67、4.68,P<0.01;HeLa:t=7.94、9.81、15.12,P<0.01)。敲低ZNF451的细胞非同源末端连接(NHEJ)修复效率降低(t=18.60,P<0.05)。在辐射和依托泊苷处理后,ZNF451与P53结合蛋白1(53BP1)和DNA损伤检查点介质1(MDC1)有明显的共定位。结论敲低ZNF451抑制A549和HeLa细胞增殖并诱导DNA损伤水平加剧。ZNF451可以募集至DNA损伤位点,通过与DNA损伤修复因子53BP1/MDC1共定位参与NHEJ修复。展开更多
The Szent-Gyorgyi Prize for Progress in Cancer Research is a prestigious scientific award established by the National Foundation for Cancer Research(NFCR)—a leading cancer research charitable organization in the Unit...The Szent-Gyorgyi Prize for Progress in Cancer Research is a prestigious scientific award established by the National Foundation for Cancer Research(NFCR)—a leading cancer research charitable organization in the United States that is committed to supporting scientific research and public education relating to the prevention,early diagnosis,better treatments,and ultimately,a cure for cancer.Each year,the Szent-Gyorgyi Prize honors an outstanding researcher,nominated by colleagues or peers,who has contributed outstanding,significant research to the fight against cancer,and whose accomplishments have helped improve treatment options for cancer patients.The Prize also promotes public awareness of the importance of basic cancer research and encourages the sustained investment needed to accelerate the translation of these research discoveries into new cancer treatments.This report highlights the pioneering work led by the 2015 Prize winner,Dr.Frederick Alt.Dr.Alt's work in the area of cancer genetics over four decades has helped to shape the very roots of modern cancer research.His work continues to profoundly impact the approaches that doctors around the globe use to diagnose and treat cancer.In particular,his seminal discoveries of gene amplification and his pioneering work on molecular mechanisms of DNA damage repair have helped to usher in the era of genetically targeted therapy and personalized medicine.展开更多
基金Supported by The Grants from the Ministry of EducationCulture+7 种基金SportsScience and Technology of Japanthe Ministry of HealthLabour and Welfare of Japanthe National Institute of Biomedical Innovationthe Asahi Glass Foundationthe Ichiro Kanehara Foundationthe Program for Cultivating Global Leaders in Heavy Ion Therapeutics and Engineering
文摘Recently, an epoch-making genome engineering technology using clustered regularly at interspaced short palindromic repeats(CRISPR) and CRISPR associated(Cas) nucleases, was developed. Previous technologies for genome manipulation require the time-consuming design and construction of genome-engineered nucleases for each target and have, therefore, not been widely used in mouse research where standard techniques based on homologous recombination are commonly used. The CRISPR/Cas system only requires the design of sequences complementary to a target locus, making this technology fast and straightforward. In addition, CRISPR/Cas can be used to generate mice carrying mutations in multiple genes in a single step, an achievement not possible using other methods. Here, we review the uses of this technology in genetic analysis and manipulation, including achievements made possible to date and the prospects for future therapeutic applications.
文摘拟轮枝镰孢菌(Fusarium verticillioides)是引起玉米茎基腐病和穗粒腐病的主要病原菌之一,严重威胁玉米的产量和品质。为了深入研究拟轮枝镰孢菌致病基因的功能,对该菌中非同源末端连接(non-homologous end joining,NHEJ)途径中的2个关键基因FvKu70和FvKu80分别进行了基因敲除以创制高效的基因敲除菌株,并比较了野生型菌株和突变体菌株在营养生长速率、菌落形态、产孢量、对玉米的致病力和基因敲除效率等方面的差异。研究结果表明,FvKu70和FvKu80的基因缺失突变体与野生型FvLNF15-11相比,在PDA平板上的形态特征(如菌丝形态、生长速率、菌落直径、产孢量)没有明显差异,对玉米茎秆的致病力也类似。此外,选择尿嘧啶生物合成相关基因FvpyrG作为敲除的靶基因,分析了FvKu70或FvKu80缺失突变体菌株的同源重组效率,结果显示突变体菌株均显著高于野生型,其中ΔFvKu70的同源重组效率最高。综上所述,FvKu70或FvKu80基因缺失突变体可以快速又高效地实现拟轮枝镰孢菌的基因敲除,为进一步研究该菌的功能基因提供了技术支持。
文摘在自然界中,植物会遭受各种环境或内源因素导致的DNA损伤,其中DNA双链断裂(double strand breaks,DSBs)的影响最为严重,如果修复不当,将导致基因组不稳定、基因突变甚至细胞死亡。一方面,植物进化出了强大且有序的损伤修复机制,以确保其存活及正常繁衍;另一方面,基于修复过程的容错性及致突变性,T-DNA插入、基因编辑、物理诱变等技术广泛应用于动植物品种改良。相较于哺乳动物,植物DSBs修复通路及其分子机制报道较为有限。本文综述了植物对DSBs损伤的响应、主要修复途径及关键因子,介绍了通路机制尚未完全解析的替代末端连接(alternative end joining,Alt-EJ)的最新研究进展;此外,探讨了重离子束引起的植物DSBs修复特征和多途径选择,以及基于不同DSBs修复途径的基因编辑技术的研究进展,旨在为深入了解植物DSBs损伤响应及修复的分子机制和研发高效生物育种技术提供参考。
文摘目的建立含p I-SCEⅠ酶切位点的总的非同源末端连接(total non-homologous end joining,Total-NHEJ)和非经典末端连接(alternative end joining,A-EJ)修复底物的细胞株,设置特定的流式细胞术参数,定量检测依托泊苷(etoposide,VP-16)对非同源末端连接(Non-homologous end joining,NHEJ)修复的影响。方法本实验通过脂质体转染含修复底物的质粒,嘌呤霉素筛选,构建起NHEJ修复系统的稳定细胞株;运用流式细胞术和PCR技术对所构建的细胞株的基因组DNA进行分析与鉴定;运用细胞免疫荧光及基因组DNA琼脂糖凝胶电泳检测VP-16诱导的DNA双链断裂(DNA double strand break,DSB)损伤,运用流式细胞术定量检测VP-16对NHEJ修复的影响。结果在所筛选的细胞中的各得到2株阳性细胞株Total-NHEJ和2株阳性细胞株A-EJ。VP-16作用浓度和时间的增加,Total-NHEJ和A-EJ修复效率增加。结论 VP-16诱导DNA损伤的同时,促进总NHEJ修复和A-EJ修复,修复呈现剂量和时间依赖性,但随着浓度和作用时间的增加,VP-16致DSB的损伤能力超过修复能力。
基金supported by grants from National Natural Sciences Foundation of China (No.30872237)the National Basic Research Program of China(No.2007CB512900)
文摘Hepatitis B virus(HBV)-induced hepatocellular carcinoma(HCC) is one of the most fre-quently occurring cancers.Hepadnaviral DNA integrations are considered to be essential agents which can promote the process of the hepatocarcinogenesis.More and more researches were designed to find the relationship of the two.In this study,we investigated whether HBV DNA integration occurred at sites of DNA double-strand breaks(DSBs),one of the most detrimental DNA damage.An 18-bp I-SceI homing endonuclease recognition site was introduced into the DNA of HepG2 cell line by stable DNA transfection,then cells were incubated in patients’ serum with high HBV DNA copies and at the same time,DSBs were induced by transient expression of I-SceI after transfection of an I-SceI expression vector.By using nest PCR,the viral DNA was detected at the sites of the break.It appeared that integra-tion occurred between part of HBV x gene and the I-SceI induced breaks.The results suggested that DSBs,as the DNA damages,may serve as potential targets for hepadnaviral DNA insertion and the integrants would lead to widespread host genome changes necessarily.It provided a new site to investi-gate the integration.
基金Supported by The DOD Innovator and Scholar Concept Award,No.W81XWH-12-1-0372
文摘Over the past few decades, major strides have advanced the techniques for early detection and treatment of cancer. However, metastatic tumor growth still accounts for the majority of cancer-related deaths worldwide. In fact, breast cancers are notorious for relapsing years or decades after the initial clinical treatment, and this relapse can vary according to the type of breast cancer. In estrogen receptor-positive breast cancers, late tumor relapses frequently occur whereas relapses in estrogen receptor-negative cancers or triple negative tumors arise early resulting in a higher mortality risk. One of the main causes of metastasis is tumor dormancy in which cancer cells remain concealed, asymptomatic, and untraceable over a prolonged period of time. Under certain conditions, dormant cells can re-enter into the cell cycle and resume proliferation leading to recurrence. However, the molecular and cellular regulators underlying this transition remain poorly understood. To date, three mechanisms have been identified to trigger tumor dormancy including cellular, angiogenic, and immunologic dormancies. In addition, recent studies have suggested that DNA repair mechanisms may contribute to the survival of dormant cancer cells. In this article, we summarize the recent experimental and clinical evidence governing cancer dormancy. In addition, we will discuss the role of DNA repair mechanisms in promoting the survival of dormant cells. This information provides mechanistic insight to explain why recurrence occurs, and strategies that may enhance therapeutic approaches to prevent disease recurrence.
文摘目的探究SUMO E3连接酶(zinc finger protein 451,ZNF451)介导非小细胞肺癌A549细胞和宫颈癌HeLa细胞DNA损伤修复的功能及机制。方法采用γ射线或依托泊苷处理A549细胞和HeLa细胞,CCK-8法检测细胞增殖活力,蛋白免疫印迹法检测蛋白表达量。DR-GFP质粒系统检测DNA损伤修复水平,免疫荧光法检测蛋白的空间定位。结果依托泊苷抑制了ZNF451的表达并呈剂量及时间依赖性。30、50、80μmol/L依托泊苷处理,敲低ZNF451后的A549和HeLa细胞增殖活力显著降低(A549:t=27.62、25.61、5.32,P<0.01;HeLa:t=30.77、21.28、4.18,P<0.01)。ZNF451在DNA损伤位点处募集并与γ-H2AX存在胞内共定位和内源性的相互作用,且在30、50、80μmol/L依托泊苷处理的ZNF451敲低细胞中,γ-H2AX的表达水平显著增加(A549:t=6.12、10.67、4.68,P<0.01;HeLa:t=7.94、9.81、15.12,P<0.01)。敲低ZNF451的细胞非同源末端连接(NHEJ)修复效率降低(t=18.60,P<0.05)。在辐射和依托泊苷处理后,ZNF451与P53结合蛋白1(53BP1)和DNA损伤检查点介质1(MDC1)有明显的共定位。结论敲低ZNF451抑制A549和HeLa细胞增殖并诱导DNA损伤水平加剧。ZNF451可以募集至DNA损伤位点,通过与DNA损伤修复因子53BP1/MDC1共定位参与NHEJ修复。
文摘The Szent-Gyorgyi Prize for Progress in Cancer Research is a prestigious scientific award established by the National Foundation for Cancer Research(NFCR)—a leading cancer research charitable organization in the United States that is committed to supporting scientific research and public education relating to the prevention,early diagnosis,better treatments,and ultimately,a cure for cancer.Each year,the Szent-Gyorgyi Prize honors an outstanding researcher,nominated by colleagues or peers,who has contributed outstanding,significant research to the fight against cancer,and whose accomplishments have helped improve treatment options for cancer patients.The Prize also promotes public awareness of the importance of basic cancer research and encourages the sustained investment needed to accelerate the translation of these research discoveries into new cancer treatments.This report highlights the pioneering work led by the 2015 Prize winner,Dr.Frederick Alt.Dr.Alt's work in the area of cancer genetics over four decades has helped to shape the very roots of modern cancer research.His work continues to profoundly impact the approaches that doctors around the globe use to diagnose and treat cancer.In particular,his seminal discoveries of gene amplification and his pioneering work on molecular mechanisms of DNA damage repair have helped to usher in the era of genetically targeted therapy and personalized medicine.
