在早期哺乳动物胚胎中,DNA甲基化的一个独特的调节阶段
Zachary D Smith1, Michelle M Chan, Tarjei S Mikkelsen
1Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.
Nature
|March 30, 2012
概括
哺乳动物胚胎发生涉及动态的DNA甲基化变化. 新的基本分辨率地图揭示了早期胚胎中保持着独特的卵细胞衍生甲基化模式,挑战了现有的模型.
科学领域:
- 表观遗传学和发育生物学
- 基因组学和生物信息学
背景情况:
- 哺乳动物胚胎生成的特点是动态DNA甲基化对于发育至关重要.
- 现有的父性基因组脱甲基化模型基于有限的数据.
- 在早期胚胎发生过程中缺乏DNA甲基化的基底分辨率图.
研究的目的:
- 为了生成基因组规模,基底分辨率的DNA甲基化地图,在小鼠体内和早期胚胎.
- 完善对哺乳动物植入前发育过程中的DNA甲基化动态的理解.
- 为了识别由卵细胞和精子所贡献的独特甲基化模式.
主要方法:
- 鼠标精子,卵细胞,胚胎和植入后胚胎的全基因组双硫酸盐测序 (WGBS).
- 生物信息分析以生成基解析度的DNA甲基化地图.
- 差异甲基化区域 (DMRs) 的识别和表征.
主要成果:
- 卵细胞表现出全局低甲基化,特别是在特定的反元素,与精子相比,胚胎甲基化较低.
- 卵子细胞贡献独特的DMR,包括CpG岛屿促进体,在早期胚胎中保持,但在体细胞中丢失.
- 精子贡献的DMRs主要是基因间的,并成为超甲基化后胚芽细胞阶段.
结论:
- 提供了早期哺乳动物胚胎中DNA甲基化动态的全面的基准分辨率时间表.
- 揭示了新的,来自卵细胞的甲基化模式,在早期发育过程中是暂时的.
- 挑战并完善了哺乳动物胚胎生成中全基因组脱甲基和重编程的现有模型.
相关概念视频
Epigenetic Regulation
Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
Epigenetic Regulation
Epigenetic changes alter the physical structure of the DNA without changing the genetic sequence and often regulate whether genes are turned on or off. This regulation ensures that each cell produces only proteins necessary for its function. For example, proteins that promote bone growth are not produced in muscle cells. Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer.
X-chromosome...
X-chromosome...
Genomic Imprinting and Inheritance
Diploid organisms inherit genetic material through chromosomes from both parents. Copies of the same gene are known as alleles. In most cases, both alleles are simultaneously expressed and allow various cellular processes to function optimally. If one of the alleles is missing or mutated, the expression of the other allele can compensate; however, this is not true for all genes.
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
The expression of some genes depends on which parent passed the gene to the offspring, through a phenomenon known as...
Inheritance of Chromatin Structures
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying DNA...
Cleavage and Blastulation
After a large-single-celled zygote is produced via fertilization, the process of cleavage occurs while zygotes travel through the uterine tube. Cleavage is a mitotic cell division that does not result in growth. With each round of successive cell division, daughter cells get increasingly smaller.
Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...


