植物DNA甲基化研究进展

植物DNA甲基化是导致转基因沉默的直接和主要因素。甲基化的出现严重制约了植物基因工程的商业化生产。本将对植物DNA甲基化的机制、作用等问题作一综述。     

DNA甲基化的影响因素及对基因表达的调控

DNA甲基化是一种由DNA甲基转移酶介导的主要表观遗传修饰方式,是调节基因组功能的重要途径。本文重点综述了影响DNA甲基化的主要因素以及DNA甲基化与基因表达调控的关系。     

DNA甲基化异常与肿瘤间关系的研究进展

DNA的甲基化及甲基化异常在人体发育和肿瘤的发生中起着至关重要的作用。文中主要综述了几十年来人们对 DNA甲基化异常与基因转录及肿瘤发生之间关系的研究进展 ,尤其是最近的研究突破。     

DNA 甲基化及其生物学功能

DNA甲基化是表观遗传修饰的重要组成成分,是一种重要的基因表达调控机制。本文在介绍DNA甲基化的形成及其修饰方式的基础上论述了DNA甲基化的生物学功能。     

表观遗传学中的DNA可逆化学修饰

DNA是遗传信息的载体,也是生物个体以及物种的整个生命周期的蓝图。DNA在这整个生命周期中保持高度稳定。DNA的可逆化学修饰在哺乳动物的细胞分化、个体发育等过程中起到重要作用。本文主要关注针对DNA中胞嘧啶的甲基化与去甲基化动态变化及功能的相关前沿研究进展。     

美国科学家发现人类基因组随年龄改变

据2008年7月2日《新民晚报》援引新华社7月2日电,美国约翰斯·霍普金斯大学的科研人员,对600名相关研究项目的参与者的DNA序列进行了比较研究。这些参与者先后于1991年,以及2002至2005年间提供DNA样品。研究人员对111个样本中的DNA甲基化水平作了分析,发现大约有三分之一样本中的甲基化水平随时间而改变。     

DNA甲基化异常与肿瘤发生的研究

DNA甲基化是真核生物DNA的正常内源性修饰方式 ,它由DNA甲基化转移酶催化发生。但DNA甲基化异常在肿瘤发生中却起着极为重要的作用 ,它主要表现为抑癌基因高甲基化所致的基因失活和原癌基因低甲基化所致的基因激活 ,引起与细胞增殖、分化相关基因表达异常 ,造成细胞恶变形成肿瘤。文章总结了DNA甲基化异常对肿瘤相关基因表达的影响 ,在肿瘤发生中的可能机制及针对高甲基化的治疗方案     

DNA并非遗传的全部

众所周知，DNA是遗传信息的携带，遗传现象主要是由基因决定的。但是，近几年来科学家发现，朊病毒是一种可遗传的蛋白质粒子；DNA甲基化也导致一些遗传现象的发生；性状间的相互制约也可引起不受基因控制的表型出现……这些现象说明DNA并非遗传的全部。     

DNA并非遗传的全部

众所周知 ,DNA是遗传信息的携带者 ,遗传现象主要是由基因决定的。但是 ,近几年来科学家发现 ,朊病毒是一种可遗传的蛋白质粒子 ;DNA甲基化也导致一些遗传现象的发生 ;性状间的相互制约也可引起不受基因控制的表型出现……这些现象说明DNA并非遗传的全部。     

动物克隆中供体核DNA的甲基化重编程

动物克隆中去核卵母细胞中的供体核DNA会发生甲牡化重编程。克隆胚胎DNA重编程过程中的去甲基化和甲基化过程存在的一些异常会影响胚胎发育;     

表观遗传学与肿瘤

表观遗传学是研究基因的核苷酸序列不发生改变的情况下,基因表达或蛋白表达发生可遗传的变化,但又可以通过细胞发育和增殖而稳定遗传现象的一门遗传学分支学科．表观遗传学的研究内容包括DNA甲基化、组蛋白共价修饰、mRNA编辑、染色体重塑、基因沉默等．其调控机制是：细胞内功能基因的选择性激活或灭活．表观基因相对于整个基因组本身,提供了更有序、更特定的基因信息．表观遗传的异常会导致表型的改变,表现为人类疾病,如肿瘤．因此,随着人们对表观遗传学认识的深入,表观遗传学将成为生物医学研究领域的重点．     

Molecular modeling study of the effect of base methylation on internal interactions and motions in DNA and implication to B-Z conformation change

1. Introduction Experimental studies have shown that a DNA molecule with alternating pyrimidine-purine sequence can adopt a left-handed, double-helical Z-DNA conformation [1,2]. Such structural changes of DNA occur as a consequence of environmental conditions such as at salt concentration above 4 mol/L NaCl [1,2] or through certain chemical modification such as methylation [1] or bromination [2,3] of bases at physiological conditions. These structural changes and chemical modifications …     

DNA Methylation: A Mechanism for Embedding Early Life Experiences in the Genome

Although epidemiological data provide evidence that early life experience plays a critical role in human development, the mechanism of how this works remains in question. Recent data from human and animal literature suggest that epigenetic changes, such as DNA methylation, are involved not only in cellular differentiation but also in the modulation of genome function in response to early life experience affecting gene function and the phenotype. Such modulations may serve as a mechanism for life‐long genome adaptation. These changes seem to be widely distributed across the genome and to involve central and peripheral systems. Examining the environmental circumstances associated with the onset and reversal of DNA methylation will be critical for understanding risk and resiliency.     

Epigenetic regulation of adipocyte differentiation and adipogenesis

It is generally agreed that adipocytes originate from mesenchymal stem cells in what can be divided into two processes: determination and differentiation. In the past decade, many factors associated with epigenetic signals have been proved to be pivotal for the appropriate timing of adipogenesis progression. A large number of coregulators at critical gene promoters set up specific patterns of DNA methylation, histone acetylation and methylation, and nucleosome rearrangement, that act as an epigenetic code to modulate the correct progress of adipocyte differentiation and adipogenesis during adipogenesis. In this review, we focus on the functions and roles of epigenetic processes in preadipocyte differentiation and adipogenesis.     

DNA与抗生素——土霉素相互作用

DN（A脱氧核糖酸）是所有生命的基本遗传物质,是决定生命的最重要的一种化学物质.对DNA的研究是生命科学研究领域中极其重要的内容.近20年,DNA的研究和技术成果日新月异,DNA重组技术已经迅速进入人类生活.尤其在医药中,DNA与其靶向分子相互作用的研究对阐述一些引起抗肿瘤、抗病毒药物及致癌物作用机理、进一步指导人工核酸的合成及DNA高级结构研究都具有重要意义.本文用循环伏安法（CV）和差示脉冲法（DPV）对不同浓度的DNA以不同的速度来扫描,同时把电极行修饰后进行上述扫描,讨论后得出最佳实验条件及DNA与土霉素的相互作用原理.     

A Methylome‐Wide Association Study of Trajectories of Oppositional Defiant Behaviors and Biological Overlap With Attention Deficit Hyperactivity Disorder

In 671 mother–child (49% male) pairs from an epidemiological birth cohort, we investigated (a) prospective associations between DNA methylation (at birth) and trajectories (ages 7–13) of oppositional defiant disorder (ODD), and the ODD subdimensions of irritable and headstrong; (b) common biological pathways, indexed by DNA methylation, between ODD trajectories and attention deficit hyperactivity disorder (ADHD); (c) genetic influence on DNA methylation; and (d) prenatal risk exposure associations. Methylome‐wide significant associations were identified for the ODD and headstrong, but not for irritable. Overlap analysis indicated biological correlates between ODD, headstrong, and ADHD. DNA methylation in ODD and headstrong was (to a degree) genetically influenced. DNA methylation associated with prenatal risk exposures of maternal anxiety (headstrong) and cigarette smoking (ODD and headstrong).     

跨损伤DNA合成及其在肿瘤治疗中的应用

跨损伤合成（translesion synthesis,TLS）是一种利用特殊的DNA聚合酶介导的修复过程,是细胞应答DNA损伤时的一种保守的耐受机制。由于TLS能使细胞耐受DNA损伤,降低肿瘤细胞对化疗药物或者放疗的敏感性,因此它可能是肿瘤产生耐药性或者辐射耐受性的潜在机制。通过靶向跨损伤合成通路,可提高包括神经胶质瘤在内的多种肿瘤患者的治疗疗效。     

DNA methylation in the tumor microenvironment

The tumor microenvironment (TME) plays an important role in supporting cancer progression. The TME is composed of tumor cells, the surrounding tumor-associated stromal cells, and the extracellular matrix (ECM). Crosstalk between the TME components contributes to tumorigenesis. Recently, one of our studies showed that pancreatic ductal adenocarcinoma (PDAC) cells can induce DNA methylation in cancer-associated fibroblasts (CAFs), thereby modifying tumor-stromal interactions in the TME, and subsequently creating a TME that supports tumor growth. Here we summarize recent studies about how DNA methylation affects tumorigenesis through regulating tumorassociated stromal components including fibroblasts and immune cells. We also discuss the potential for targeting DNA methylation for the treatment of cancers.