全基因组"重新"建模核位的位置
1Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY 10065, USA. rsadeh@rockefeller.edu
Cell
|October 18, 2011
概括
染色质重塑剂在酵母中组织核细胞在起始点附近. 在人类中",锁定"的核体可能会作为核体阵列形成的障碍,揭示基因组组织机制.
科学领域:
- 基因组学就是基因组学.
- 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.
背景情况:
- 核细胞是真核生物中DNA包装的基本单元.
- 了解核细胞组织对于基因调节至关重要.
- 最近的进展使得核位定位的全基因组映射成为可能.
研究的目的:
- 为了研究推动基因组跨基因组核细胞组织的因素.
- 为了区分DNA序列和染色质重塑剂的作用.
- 在酵母和人类中提出核细胞定位模型.
主要方法:
- 在酵母和人类细胞中全基因组核细胞映射.
- 计算分析以将核细胞位与DNA序列特征相关联.
- 分析染色体重塑活性及其对核细胞占用率的影响.
主要成果:
- 染色体重塑剂在酵母体中转录起始点周围的核体定位中发挥着关键作用.
- 在人类基因组中识别出特定的核体,这些核体似乎"锁定"在原地.
- 这些"锁定"的核酶体可以作为更广泛的核酶体数组的组织中心.
结论:
- 核细胞组织受到内在DNA特性和外在因素 (如染色体重塑剂) 的影响.
- 不同的机制控制着不同物种中核细胞的定位,突出了进化适应.
- "锁定"核细胞模型为人类的高阶染色体结构提供了新的视角.
相关概念视频
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...
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.
02:35Chromatin 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...
02:33The Nucleosome
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...
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
01:30Crossing Over
Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I, duplicated...
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...