基因素H3K9的逐步甲基化将异染色素定位在核外围
Benjamin D Towbin1, Cristina González-Aguilera, Ragna Sack
1Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
Cell
|September 4, 2012
概括
耗尽S-adenosylmethionine合成酶会释放C. elegans中的异染色素. 这一过程涉及MET-2和SET-25基因组甲基转移酶,它们建立了H3K9甲基化,并将异色素定在核外围.
科学领域:
- 细胞生物学 细胞生物学
- 遗传学 是一个遗传学.
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
背景情况:
- 将转录抑制的异色素结到核外围的机制尚不清楚.
- 异染色素局部化对于保持基因组稳定性和调节基因表达至关重要.
研究的目的:
- 为了确定涉及到核接的因素,异性染色素.
- 为了阐明S-adenosylmethionine合成酶和特定的组胺甲基转移酶在异色染色体局部化中的作用.
主要方法:
- 在Caenorhabditis elegans胚胎中进行全基因组RNA干扰 (RNAi) 查.
- 对基因组甲基转移酶 (HMTs) 的分析,包括MET-2和SET-25.
- 对异色色变基因和原生染色体臂局部化的评估.
主要成果:
- S-adenosylmethionine (SAM) 合成酶的耗尽在全球范围内降低了组织蛋白甲基化,并从核外围释放了异染色素.
- 丢失MET-2和SET-25 HMTs的副本SAM合成酶的耗尽,破坏异性染色体的附着.
- MET-2和SET-25连续作用以建立H3K9甲基化,SET-25沉积H3K9me3并形成周核点.
结论:
- 在C. elegans中,SAM合成酶和HMTs MET-2和SET-25对于将异性染色质在核外围至关重要.
- 一个连续的HMT路径,MET-2接着SET-25,建立了H3K9甲基化,对异色素定位至关重要.
- SET-25表现出依赖其产物的自我强化的周核局部化,这表明异色素蛋白传播的机制.
相关概念视频
Heterochromatin
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 9th...
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 9th...
Heterochromatin
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 9th...
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 9th...
Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
Spreading of Chromatin Modifications
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 is an enzyme that can...
Writers
The writer is an enzyme that can...
Nucleosome Remodeling
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA inaccessible to DNA binding proteins such as DNA polymerase and RNA polymerase. Hence, the fundamental problem is to ensure access to DNA when appropriate, despite the compact and protective chromatin structure.
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Chromatin Position Affects Gene Expression
Chromatin is the massive complex of DNA and proteins packaged inside the nucleus. The complexity of chromatin folding and how it is packaged inside the nucleus greatly influences access to genetic information. Generally, the nucleus' periphery is considered transcriptionally repressive, while the cell's interior is considered a transcriptionally active area.
Topologically Associated Domains (TADs)
The 3-dimensional positioning of chromatin in the nucleus influences the timing and level of...
Topologically Associated Domains (TADs)
The 3-dimensional positioning of chromatin in the nucleus influences the timing and level of...


