相关实验视频
Updated: May 27, 2026
09:32
Deciphering High-Resolution 3D Chromatin Organization via Capture Hi-C
Published on: October 14, 2022
沉声的结构基础: Sir3 BAH 域复合在一个核细胞体的3.0 Å分辨率
Karim-Jean Armache1, Joseph D Garlick, Daniele Canzio
1Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.
Science (New York, N.Y.)
|November 19, 2011
概括
在真核生物中,基因沉默依赖于Sir3蛋白与核细胞的相互作用. 晶体结构揭示了这些相互作用和修饰如何形成沉默的染色质域,这对细胞命运至关重要.
科学领域:
- 分子生物学分子生物学
- 染色体生物学 染色体生物学
- 结构生物学 结构生物学
背景情况:
- 基因沉默对于真核细胞命运调节至关重要.
- 染色体结构在保持沉默状态方面发挥着关键作用.
- 静音信息调节器 (Sir) 蛋白质,包括Sir3,对于调节酵母中的交配类型至关重要.
研究的目的:
- 为了确定酵母 Sir3 BAH 域与核细胞核粒子复合的晶体结构.
- 阐明产生沉默色素域的分子相互作用.
- 为了了解特定的组织蛋白修饰如何影响沉默复合体的形成.
主要方法:
- 在3.0安格斯特罗姆分辨率的X射线晶体学.
- 对Sir3 BAH域和核细胞核粒子复合体的结构分析.
- 将遗传突变映射到观察到的分子相互作用.
主要成果:
- 晶体结构揭示了Sir3 BAH域与核细胞表面之间广泛的分子相互作用.
- 观察到的相互作用解释了许多记录下来的影响基因沉默的遗传突变.
- 确定了核细胞和BAH域中的结构重组.
- 该结构提供了关于H4K16和H3K79的共价变异如何调节沉默复合体形成的洞察力.
结论:
- Sir3 BAH 域直接与核体相互作用,以建立沉默的染色体.
- 确定的结构为理解基因沉默机制提供了分子基础.
- 基斯顿修饰是Sir3核酶体复合体形成和功能的关键调节者.
相关概念视频
02:10The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
01:12The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
02:32Position-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.
02:41Chromatin Structure Regulates pre-mRNA Processing
In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into functional proteins. For a long time, transcription and pre-mRNA processing were considered two independent events that occur sequentially in the cell. However, it has now been well established that transcription and pre-mRNA processing are two simultaneous processes that are precisely regulated inside the cell.
The chromatin structure, especially...
The chromatin structure, especially...
02:30siRNA - Small Interfering RNAs
Small interfering RNAs, or siRNAs, are short regulatory RNA molecules that can silence genes post-transcriptionally, as well as the transcriptional level in some cases. siRNAs are important for protecting cells against viral infections and silencing transposable genetic elements.
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
02:54Nucleosome 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...