对DNMT3A的自身抑制和组织素H3诱导激活的结构洞察力
11] Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China [2] State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China.
Nature
|November 11, 2014
概括
基因甲基转移酶3A (DNMT3A) 通过自身结构被抑制,但被基因素H3尾部激活. 这种基因组相互作用释放自身抑制,使DNA在特定基因组位点的甲基化.
科学领域:
- 表观遗传学和分子生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 基因甲基化是一种关键的表观遗传修饰,调节基因表达,印记和遗传.
- 新型DNA甲基转移酶DNMT3A和DNMT3B在哺乳动物胚胎发生过程中建立甲基化模式.
- 一种相关的蛋白质DNMT3L增强了DNMT3A的活性,而组织蛋白修饰指导了DNA甲基化建立.
研究的目的:
- 阐明 histone H3 刺激 DNMT3A 活动的分子机制.
- 研究DNMT3A的自身抑制机制及其调节.
- 为了确定DNMT3A激活的结构基础,通过素H3.
主要方法:
- 确定DNMT3A-DNMT3L (自身抑制) 和DNMT3A-DNMT3L-H3 (活性) 复合物的晶体结构.
- 生物化学试验分析酶活性和DNA结合.
- 对DNMT3A域与基因素H3.3之间的相互作用进行结构分析.
主要成果:
- DNMT3A存在于一种自抑制性构造中,其中ATRX-DNMT3-DNMT3L (ADD) 域通过阻止DNA结合来抑制催化域 (CD).
- 歇斯H3 (特别是,不是H3K4me3) 破坏ADD-CD相互作用,释放自身抑制并以DNMT3L独立的方式激活DNMT3A.
- 结构数据显示,在希斯H3结合时,ADD域发生了很大的构造变化,导致DNMT3A激活.
结论:
- 素H3结合为新型DNA甲基化提供了一个调节层,确保在适当的位置与未甲基化H3K4一起激活酶.
- 这些发现支持H3K4me3和整个哺乳动物基因组的DNA甲基化之间的负相关性.
- 这项研究揭示了DNMT3A的意想不到的自身抑制机制,这种机制由基因素H3缓解,为表观遗传调节提供了新的见解.
相关概念视频
Histone Modification
18.0K
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone...
18.0K
Histone Modification
5.1K
5.1K
Spreading of Chromatin Modifications
10.1K
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer...
Writers
The writer...
10.1K
Eukaryotic Transcription Inhibitors
11.7K
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a...
Eukaryotic transcription inhibitors usually contain two distinct domains, a...
11.7K
Heterochromatin
19.2K
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at...
19.2K
Euchromatin
9.4K
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...
9.4K


