共查询到19条相似文献,搜索用时 62 毫秒
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植物表观遗传与DNA甲基化 总被引:1,自引:0,他引:1
表观遗传在植物生长发育过程中起着极其重要的作用。甲基化是基因组DNA的一种主要表观遗传修饰形式,是调节基因功能的重要手段。介绍了植物体中胞嘧啶甲基化现象,RNA指导的DNA甲基化的信号分子、作用机制,以及与RNA介导的基因沉默机制之间的区别和RNA对转座子的表观控制。 相似文献
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植物多倍体在自然界中广泛存在,这说明拥有多套遗传物质使得多倍体的适应进化具有优势。新多倍体形成后,一些基因组范围的变化较迅速地发生在多倍体形成开端,另一些在长期进化中发生。由于受到遗传、表观等因素的影响,亲本对于新形成多倍体基因组的贡献不均衡。这种偏向于某个亲本基因组的显性优势,称为基因组印记。植物多倍体中的基因组印记表现为基因组偏向性的序列消除、不均衡基因表达、基因沉默,这些受到基因组合并及DNA甲基化、核仁显性等表观因素影响。本文旨在为多倍体基因组进化及育种的相关研究提供参考。 相似文献
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表观遗传学与人类疾病的研究进展 总被引:22,自引:0,他引:22
在过去的几年里,人们对表观遗传疾病的机理有了新的认识,这些疾病与染色质重塑、基因组印记、X染色体失活以及非编码RNA调控这4个表观遗传过程相关。这4个过程通过调节染色质结构,在染色体或基因簇水平上对基因表达进行调控;异常调控导致复杂的突变且表现为出生前后生长发育和神经功能的异常。对这些疾病的探讨为表观遗传机制的研究提供了很好的模型,进而有助于生物医学的研究。文章就表观遗传学和表观遗传疾病机制的研究进展做一综述。 相似文献
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表观遗传学与人类表观基因组计划 总被引:1,自引:0,他引:1
表观遗传学已被用来描述许多生物学过程,成为生物学与医学领域中热点的学科之一.本文简要介绍表观遗传学与表观遗传基因组学的概念、人类表观基因组计划研究的目标与意义,并阐述DNA甲基化、组蛋白修饰、染色质重塑和非编码微小RNA等表观遗传学调控基因表达的机制.我们已经认识到人类疾病基因缺损可能部分或完全与表观遗传有关.所以,研究疾病状态下非突变的、可逆的表观遗传调节,以及治疗的可能性具有重要实际意义. 相似文献
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被子植物的种子发育从双受精开始, 产生二倍体的胚和三倍体的胚乳。在种子发育和萌发过程中, 胚乳向胚组织提供营养物质, 因此胚乳对胚和种子的正常生长发育至关重要。开花植物发生基因组印迹的主要器官是胚乳。印迹基因的表达受表观遗传学机制的调控, 包括DNA甲基化和组蛋白H3K27甲基化修饰以及依赖于PolIV的siRNAs (p4-siRNAs)调控。基因组印迹的表观遗传学调控对胚乳的正常发育和种子育性具有不可或缺的重要作用。最新研究显示, 胚乳的整个基因组DNA甲基化水平降低, 而且去甲基化作用可能源于雌配子体的中央细胞。该文综述了种子发育的表观遗传学调控机制, 包括基因组印迹机制以及胚乳基因组DNA甲基化变化研究的最新进展。 相似文献
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Epigenetic reprogramming in mammalian nuclear transfer 总被引:6,自引:0,他引:6
With the exception of lymphocytes, the various cell types in a higher multicellular organism have basically an identical genotype but are functionally and morphologically different. This is due to tissue-specific, temporal, and spatial gene expression patterns which are controlled by genetic and epigenetic mechanisms. Successful cloning of mammals by transfer of nuclei from differentiated tissues into enucleated oocytes demonstrates that these genetic and epigenetic programs can be largely reversed and that cellular totipotency can be restored. Although these experiments indicate an enormous plasticity of nuclei from differentiated tissues, somatic cloning is a rather inefficient and unpredictable process, and a plethora of anomalies have been described in cloned embryos, fetuses, and offspring. Accumulating evidence indicates that incomplete or inappropriate epigenetic reprogramming of donor nuclei is likely to be the primary cause of failures in nuclear transfer. In this review, we discuss the roles of various epigenetic mechanisms, including DNA methylation, chromatin remodeling, imprinting, X chromosome inactivation, telomere maintenance, and epigenetic inheritance in normal embryonic development and in the observed abnormalities in clones from different species. Nuclear transfer represents an invaluable tool to experimentally address fundamental questions related to epigenetic reprogramming. Understanding the dynamics and mechanisms underlying epigenetic control will help us solve problems inherent in nuclear transfer technology and enable many applications, including the modulation of cellular plasticity for human cell therapies. 相似文献
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Although aberrant DNA methylation within imprinted domains has been reported in a variety of neoplastic diseases, it remains largely uncharacterized in the context of carcinogenesis. In this study, we induced T-cell lymphoma in mice by employing a breeding scheme involving mouse strains, LSL-KrasG12D and MMTV-Cre. We then systematically surveyed imprinted domains for DNA methylation changes during tumor progression using combined bisulfite restriction analysis and NGS-based bisulfite sequencing. We detected hyper- or hypo-methylation at the imprinting control regions (ICRs) of the Dlk1, Peg10, Peg3, Grb10, and Gnas domains. These DNA methylation changes at ICRs were more prevalent and consistent than those observed at the promoter regions of well-known tumor suppressors, such as Mgmt, Fhit, and Mlh1. Thus, the changes observed at these imprinted domains are the outcome of isolated incidents affecting DNA methylation settings. Within imprinted domains, DNA methylation changes tend to be restricted to ICRs as nearby somatic differentially methylated regions and promoter regions experience no change. Furthermore, detailed analyses revealed that small cis-regulatory elements within ICRs tend to be resistant to DNA methylation changes, suggesting potential protection by unknown trans-factors. Overall, this study demonstrates that DNA methylation changes at ICRs are dynamic during carcinogenesis and advocates that detection of aberrant DNA methylation at ICRs may serve as a biomarker to enhance diagnostic procedures. 相似文献
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为了适应复杂多变的生存环境,微生物通常需要在保证基因组序列不变的前提下不断调整胞内代谢网络。表观调控可以在不改变DNA序列的情况下对基因表达进行调控,因此成为细菌中重要的调控方式。作为一种DNA修饰,DNA甲基化修饰是生物体中最常见的表观调控工具。在本文中我们全面、深入解析了两种孤儿甲基转移酶:DNA腺嘌呤甲基转移酶(DNA adenine methyltransferase,Dam)和细胞周期调控甲基转移酶(Cell cycle-regulated methyltransferase,Ccr M)在原核生物中的表观调控功能。我们主要探讨了DNA甲基化参与的细胞生理过程包括DNA复制起始、DNA错配修复、基因表达调控、致病性和相变异等方面。同时,我们结合三维基因组研究技术基因组结构捕获(Chromosome conformation capture,3C)技术和新型DNA磷硫酰化修饰讨论了该领域的发展前景。 相似文献