活细胞成像显示的CTCF和凝聚素介导的染色质循环的动态
Michele Gabriele1,2,3, Hugo B Brandão1,2,3, Simon Grosse-Holz4,5
1Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
概括
动物基因组中的染色体循环是罕见的和动态的,挑战了以前的基因组折叠模型. 这项研究表明单个CTCF边界,而不是完全循环的DNA,可能主要调节功能相互作用.
科学领域:
- 基因组学
- 分子生物学
- 细胞生物学
背景情况:
- 动物基因组由CTCF和凝聚蛋白组织成循环和拓关联域 (TAD).
- 在TAD中,染色蛋白循环形成和稳定性的动态性仍在很大程度上未被描述.
研究的目的:
- 直接可视化和量化小鼠胚胎干细胞Fbn2 TAD中的染色质循环的动态.
- 研究色素环的形成,稳定性和功能影响.
主要方法:
- 使用超分辨率的活细胞成像来观察染色体循环的动态.
- 使用贝叶斯推理量化分析循环动力学.
- 专注于小鼠胚胎干细胞中的Fbn2 TAD.
主要成果:
- 发现Fbn2循环是罕见的,循环分数为3-6.5%.
- 循环的中位寿命很短,估计在10-30分钟之间.
- 在约92%的时间里,在TAD内存在凝聚性挤出环,而没有跨越两个CTCF边界.
结论:
- Fbn2 TAD是高度动态的,循环是短暂的,而不是稳定的结构.
- 单个CTCF边界似乎是功能相互作用的关键调节者,而不是完全形成的CTCF-CTCF循环.
- 这些发现挑战了CTCF和凝聚素对基因组组织和调节的现有模型.
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