相关实验视频
Updated: Jul 2, 2025
00:07
A Method to Study de novo Formation of Chromatin Domains
Published on: August 23, 2019
5.4K
动态PRC1-CBX8稳定了色素凝聚物的多孔结构
bioRxiv : the preprint server for biology
|February 26, 2024
概括
聚合体抑制复合体1 (PRC1) 形成动态的,多孔的染色质凝聚物,仍然可访问,挑战了传统的基因抑制模型. 这种结构允许动态相互作用,同时保持稳定的染色质状态.
科学领域:
- 分子生物学分子生物学
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
- 结构生物学 结构生物学
背景情况:
- 染色体紧缩是一种已知的基因抑制机制,通常与减少的转录可访问性有关.
- 精确的空间组织和由基因抑制因素压缩的染色质的动态,如多抑制综合体1 (PRC1),以前是未知的.
研究的目的:
- 阐明 PRC1.1.3 凝聚的染色质的三维结构和动态.
- 了解 PRC1 介导的染色质紧缩的分子机制及其对可访问性的影响.
主要方法:
- 使用冷电子断层扫描来确定PRC1凝聚色素的3D结构.
- 生物化学分析研究了PRC1,CBX8和染色素之间的相互作用.
主要成果:
- PRC1凝聚色素形成多孔结构,通过动态,多价值相互作用稳定.
- CBX8的内部无序区域 (IDR),特别是带正电荷的残留物,掩盖了DNA的负电荷以稳定紧缩.
- 尽管凝结体内具有静态的染色质结构,但PRC1组件仍然具有动态性,CBX8结合的染色质在分化细胞中仍然可访问.
结论:
- 这些发现挑战了刚性紧缩的多域的范式,认为它们仅仅是压制性的.
- 建议为动态和可访问的PRC1-染色体凝聚物提供一个新的机制框架.
- 这种动态可访问性可能使Polycomb组蛋白在基因调节中的作用与染色质可访问性相协调.
相关概念视频
02:15Condensins
3.5K
Condensins are large protein complexes that use ATP to fuel the assembly of chromosomes during mitosis. They transform the tangled, shapeless mass of post-interphase DNA into individualized chromosomes by compacting, organizing, and segregating chromosomal DNA.
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
3.5K
02:38Heterochromatin
12.7K
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...
12.7K
00:50Anaphase Promoting Complex
2.9K
The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
2.9K
02:54Nucleosome Remodeling
9.1K
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...
9.1K
02:25Spreading of Chromatin Modifications
8.3K
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...
8.3K
02:37Restarting Stalled Replication Forks
5.8K
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart,...
5.8K