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从DNA修复机理看细胞癌变的发生机制 总被引:3,自引:0,他引:3
DNA损伤是引起基因突变,导致细胞恶性转化的重要原因.DNA损伤的修复过程非常复杂,是与细胞周期调节、DNA复制和DNA转录等生命活动紧密相连的.首先DNA修复需要细胞周期停滞,避免DNA损伤进入子代细胞.其次,参与DNA转录的某些基因产物参与DNA损伤的识别,有利于转录链的优先修复.最后,DNA修复系统NER、MMR参与损伤修复.上述DNA修复过程任何环节的异常,都将造成DNA修复功能减弱,导致某些功能基因突变,从而导致细胞的恶性转化. 相似文献
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从凝胶中回收DNA的方法已见多种报道,其中的电洗脱法较实用,已有几种装置作为商品出售。Wu等的方法无须任何专门设备,而是在DNA电泳区带前方挖槽,槽内嵌半透膜,使样品自凝胶泳入槽内的缓冲液中。该方法说来简单,实际操作却很费劲,尤其在样品数量大或重复操作时,更觉不便。我们按照Wu等的工作原理,制成一种电洗脱器,可使DNA的回收操作变得简单而高效。 相似文献
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水稻基因组DNA微量提取 总被引:2,自引:0,他引:2
随着植物学向分子水平的深入发展,研究中经常需要获得高质量的植物DNA样品,因此,建立植物DNA提取与纯化的常规实验方法对教学和科研都显得非常必要。介绍一种快速提取微量DNA的方法,该方法简单易行,无需任何特殊设备,所需样品量少,提取的DNA纯度高,可满足以PCR扩增为基础的实验需要。 相似文献
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以外源红细胞生成素cDNA的表达产物为指标,研究了运载DNA和重组表达质粒的构象对电穿孔转染CHO细胞的效率的影响.结果250mg/L的运载DNA可使外源基因表达水平提高3倍;线性化质粒DNA比超螺旋DNA更适合于用电穿孔方法获得永久表达.这一结果提示,运载DNA的存在和质粒DNA的线性化对提高电穿孔转染CHO细胞的效率是必须的. 相似文献
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一种蜘蛛基因组DNA的简易提取方法 总被引:6,自引:0,他引:6
本文介绍了1种改进的蜘蛛基因组DNA的提取方法.通过与传统DNA提取方法的比较,本方法具有可在常温条件下进行、DNA得率高、简便、经济等优势. 相似文献
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CTAB结合DNA凝胶回收试剂盒提取食用菌DNA 总被引:4,自引:1,他引:3
目的:为探索从食用菌子实体中快速分离和纯化DNA的方法.方法:以三种栽培的食用菌为材料,采用CTAB结合DNA凝胶回收试剂盒进行基因组DNA的分离和纯化.结果:与对照相比,结合法提取DNA样品的电泳条带更规则、清晰,并且DNA的酶切效率显著高于对照.结论:该结合法是一种快捷、高效提取纯化食用菌子实体DNA的方法. 相似文献
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Lin-Yu Lu Henry Kuang Gautam Korakavi Xiaochun Yu 《The Journal of biological chemistry》2015,290(2):851-860
The maintenance of DNA methylation in nascent DNA is a critical event for numerous biological processes. Following DNA replication, DNMT1 is the key enzyme that strictly copies the methylation pattern from the parental strand to the nascent DNA. However, the mechanism underlying this highly specific event is not thoroughly understood. In this study, we identified topoisomerase IIα (TopoIIα) as a novel regulator of the maintenance DNA methylation. UHRF1, a protein important for global DNA methylation, interacts with TopoIIα and regulates its localization to hemimethylated DNA. TopoIIα decatenates the hemimethylated DNA following replication, which might facilitate the methylation of the nascent strand by DNMT1. Inhibiting this activity impairs DNA methylation at multiple genomic loci. We have uncovered a novel mechanism during the maintenance of DNA methylation. 相似文献
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Mitochondrial DNA Repair Pathways 总被引:5,自引:0,他引:5
It has long been held that there is no DNA repair in mitochondria. Early observations suggestedthat the reason for the observed accumulation of DNA damage in mitochondrial DNA is thatDNA lesions are not removed. This is in contrast to the very efficient repair that is seen inthe nuclear DNA. Mitochondrial DNA does not code for any DNA repair proteins, but it hasbeen observed that a number of repair factors can be found in mitochondrial extracts. Mostof these participate in the base excision DNA repair pathway which is responsible for theremoval of simple lesions in DNA. Recent work has shown that there is efficient base excisionrepair in mammalian mitochondria and there are also indications of the presence of morecomplex repair processes. Thus, an active field of mitochondrial DNA repair is emerging. Anunderstanding of the DNA repair processes in mammalian mitochondria is an important currentchallenge and it is likely to lead to clarification of the etiology of the common mutations anddeletions that are found in mitochondria, and which are thought to cause various humandisorders and to play a role in the aging phenotype. 相似文献
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DNA依赖蛋白激酶研究进展 总被引:3,自引:0,他引:3
DNA依赖蛋白激酶由Ku异二聚体和DNA-PKcs组成,结合Ku蛋白后,DNA-PK激酶活性激活,DNA依赖蛋白激酶具有多功能性,参与DNA修复、基因重组以及复制、转录等多种细胞学过程. 相似文献
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《Critical reviews in biochemistry and molecular biology》2013,48(2):151-181
AbstractThe DNA double helix exhibits local sequence-dependent polymorphism at the level of the single base pair and dinucleotide step. Curvature of the DNA molecule occurs in DNA regions with a specific type of nucleotide sequence periodicities. Negative supercoiling induces in vitro local nucleotide sequence-dependent DNA structures such as cruciforms, left-handed DNA, multistranded structures, etc. Techniques based on chemical probes have been proposed that make it possible to study DNA local structures in cells. Recent results suggest that the local DNA structures observed in vitro exist in the cell, but their occurrence and structural details are dependent on the DNA superhelical density in the cell and can be related to some cellular processes. 相似文献
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The faithful transmission of genetic information from a mother to daughter cells can only occur if the integrity of the genome is preserved. DNA transactions within cells are tightly regulated to prevent DNA damage. When events that challenge genome integrity do occur, a complex web of DNA damage response pathways comes into play. Studies in model organisms have contributed significantly to the understanding of these pathways. In the last decade, the development of functional genomics techniques in S.cerevisiae has ushered in systematic approaches for the study of complex cellular processes. These methods have enabled the systematic interrogation of the DNA damage response. 相似文献
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DNA甲基化是最主要的表观遗传修饰之一,主要发生在胞嘧啶第五位碳原子上,称为5-甲基胞嘧啶。哺乳动物DNA甲基化由从头DNA甲基转移酶DNMT3A/3B在胚胎发育早期建立。细胞分裂过程中甲基化模式的维持由DNA甲基转移酶DNMT1实现。TET家族蛋白氧化5-甲基胞嘧啶成为5-羟甲基胞嘧啶、5-醛基胞嘧啶和5-羧基胞嘧啶,从而起始DNA的去甲基化过程。这些DNA甲基化修饰酶精确调节DNA甲基化的动态过程,在整个生命发育过程中发挥重要作用,其失调也与多种疾病发生密切相关。本文对近年来DNA甲基化修饰酶的结构与功能研究进行讨论。 相似文献
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Single-stranded DNA (ssDNA) intermediates are formed in multiple cellular processes, including DNA replication and recombination. Here, we describe a quantitative polymerase chain reaction (qPCR)-based assay to quantitate ssDNA intermediates, specifically the 3′ ssDNA product of resection at specific DNA double-strand breaks induced by the AsiSI restriction enzyme in human cells. We protect the large mammalian genome from shearing by embedding the cells in low-gelling-point agar during genomic DNA extraction and measure the levels of ssDNA intermediates by qPCR following restriction enzyme digestion. This assay is more quantitative and precise compared with existing immunofluorescence-based methods. 相似文献
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Mariko Nagata Sonoko Ishino Takeshi Yamagami 《Bioscience, biotechnology, and biochemistry》2019,83(4):695-704
Replication protein A (RPA) is an essential component of DNA metabolic processes. RPA binds to single-stranded DNA (ssDNA) and interacts with multiple DNA-binding proteins. In this study, we showed that two DNA polymerases, PolB and PolD, from the hyperthermophilic archaeon Thermococcus kodakarensis interact directly with RPA in vitro. RPA was expected to play a role in resolving the secondary structure, which may stop the DNA synthesis reaction, in the template ssDNA. Our in vitro DNA synthesis assay showed that the pausing was resolved by RPA for both PolB and PolD. These results supported the fact that RPA interacts with DNA polymerases as a member of the replisome and is involved in the normal progression of DNA replication forks. 相似文献
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DNA甲基转移酶的表达调控及主要生物学功能 总被引:8,自引:0,他引:8
DNA甲基化是表观遗传学的重要部分, 同组蛋白修饰相互作用, 通过改变染色质结构, 调控基因表达。在哺乳类细胞或人体细胞中, DNA甲基化与细胞的增殖、衰老、癌变等生命现象有着重大关系。对催化DNA甲基化的DNA甲基转移酶(DNA methyltransferase, Dnmt)的研究可以揭示DNA甲基化对基因表达调控的机制, 从而研究与之相关的重要生命活动。文章以DNA甲基转移酶作为切入点, 探讨DNA甲基转移酶在基因表达调控中发挥的作用及其主要生物学功能。 相似文献