概括
基因组H2b,H2a,H3和H4在2M NaCl中形成一个稳定的四重体复合体. 这个复合体在核酶消化过程中保护DNA碎片,两个复合体屏蔽较大的DNA单元.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 染色体结构 染色体结构
背景情况:
- 基因组是染色质中的主要蛋白质,负责包装DNA.
- 了解基因组复合体的形成对于理解DNA的组织和保护至关重要.
- 之前的研究已经描述了个体的质子行为,但不是这个特定的四重复合体.
研究的目的:
- 描述由质子H2b,H2a,H3和H4组成的异型四重体复合体.
- 为了研究这种基因组复合体的结构和功能性质.
- 确定这个复合体在核酶消化过程中保护DNA碎片中的作用.
主要方法:
- 使用水力动力学技术来分析组合素复合体.
- 评估了对素消化的耐药性.
- 测量了与125 (125I) 的反应性.
- 甲诱导的交联被用来研究复杂的形成.
主要成果:
- 基因组H2b,H2a,H3和H4在2M NaCl中形成一个异型的四重体复合体.
- 该复合物表现出对素的耐药性和对125I的特异反应性,类似于染色质中的基因组.
- 甲治疗揭示了该综合体内的特定交叉连接模式.
- 该综合体展示了保护DNA碎片免受核酶消化的能力.
结论:
- 鉴定到的四重复合体基因组在结构和功能上与染色体内的基因组相似.
- 这种复合体可能在保护由详尽的核酶消化产生的小DNA碎片中发挥作用.
- 提出了两种这样的复合体,以保护由部分核酶处理形成的较大的180-200基对DNA单元.
相关概念视频
02:33The Nucleosome
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DNA in a human cell is almost 2m long and it is packed inside a tiny nucleus that is only a few microns in diameter. The level of compaction of DNA inside the nucleus is astonishing. It is organized into several sequentially higher levels of compaction to fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
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02:10The Nucleosome Core Particle
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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.
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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...
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02:32Histone Modification
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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
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Acetylation
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02:30Histone Variants at the Centromere
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Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3...
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01:19The Nucleosome
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Human DNA is almost two meters long. However, it is compressed inside a tiny nucleus measuring only a few microns in diameter. To make this degree of compaction possible, DNA is organized into several sequential levels so that it can fit into such a tiny space. The most compact form of DNA is a chromosome that can be seen under a microscope in a dividing cell.
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
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01:12The Nucleosome Core Particle
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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...
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