在混合血统的白血病细胞中,MLL-AF9调节了转录的启动
Zimei Yang1, Ge Zhang2, Ruoyu Zhao1
1Sheng Yushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
The Journal of biological chemistry
|July 13, 2024
概括
混合血统白血病融合蛋白 (MLL-FPs) 和AF9主要占据基因促进器,可能调节转录启动,而不仅仅是延长. 这挑战了人们对白血病中MLL-FP机制的现有理解.
科学领域:
- 分子生物学分子生物学
- 基因规则 基因规则
- 癌症生物学 癌症生物学
背景情况:
- 混合系白血病融合蛋白 (MLL-FPs) 涉及基因激活和MLL白血病发生,主要是通过转录延长.
- 通过MLL-FPs的功能,特别是它们在转录启动与延长中的作用,仍然不完全理解的精确机制.
研究的目的:
- 研究染色质占用模式和MLL1和AF9在基因激活中的调节作用.
- 确定MLL-FPs主要影响转录延长还是也在启动中发挥作用.
- 为了比较MLL1和MLL-AF9在红血球白血病和髓性白血病模型中的功能.
主要方法:
- 染色体免疫沉 (ChIP) 测试以确定MLL1,AF9,RNA聚合酶II,TBP和TFIIE的占用率.
- 在正常和淘汰条件下分析基因表达和HEL (人类红血球白血病) 和iMA9 (小鼠急性髓性白血病) 细胞系中的蛋白占用率.
主要成果:
- MLL1和AF9主要占据基因促销器和远端跨基因区域,类似于RNA聚合酶II.
- 尽管MLL1和AF9共占数千个基因,但它们只能共同调节一个小部分基因,并且没有相互作用.
- 缺少AF9减少了TBP和CDK9的占用,这表明它在转录启动和延长因子招募中发挥了作用.
- MLL-AF9也占据了促进者和基因间区域,其缺陷减少了TBP和TFIIE占用率,表明在启动中发挥了作用.
结论:
- MLL1和MLL-AF9在促进体和基因间区域表现出类似的染色质占用模式.
- MLL-AF9似乎调节了转录启动和延伸,这与普遍认为它仅影响延伸的观点相反.
- 这些发现为MLL-FPs在白血病发展中的机制提供了新的见解.
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