沉默的染色体允许激活器结合和PIC招募
1Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
Cell
|May 12, 2001
概括
抑制性异质色素允许转录因子结合,但阻断了基因激活. 酵母研究表明,沉默蛋白不能阻止预启动复合体的组合,但可以抑制下游的步骤,而不会改变基因素乙化.
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.
- 基因规则 基因规则
背景情况:
- 染色体结构传统上被视为阻碍转录因子对DNA可访问性的障碍.
- heterochromatin 在调节基因表达中的作用是复杂的,并未完全理解.
研究的目的:
- 为了研究SIR生成的色素如何影响转录因子和预启动复合体在酵母中的结合.
- 确定 heterochromatin 抑制转录的机制.
主要方法:
- 使用酵母热冲击基因模型系统,并配有交配型沉声器.
- 分析了转录因子 (HSF) 和预启动复合元件 (TBP,Pol II) 在异色促进体上的占用率.
- 在 heterochromatin 激活过程中检查 histone 修饰和位移.
主要成果:
- 抑制性异色素允许HSF,TBP和Pol II与促进体构成性结合.
- 这些因素与沉默蛋白和脱乙基化组织蛋白共存.
- 异色色促进体被TBP和Pol II占用,表明转录的下游阻断.
结论:
- 通过SIR介导的异色染色体抑制了前启动复合体招募的下游转录,而不是通过限制DNA访问.
- 异染色素激活可以发生在没有组织蛋白位移或乙化状态的变化的情况下.
相关概念视频
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...
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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 DNA...
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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...
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Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...


