一个分子间的二硫化物键稳定了E2A同位体,并且在生理温度下需要DNA结合
1Cell Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Cell
|December 16, 1994
概括
E2A螺旋环-螺旋环 (HLH) 蛋白质形成与二硫化物结合的同型分子,结合DNA. 减少这种结合有利于单体,使得Id和MyoD的异构化成为可能,这表明了一个新的调节机制.
科学领域:
- 分子生物学分子生物学
- 转录因子法规转录因子法规
- 蛋白质的二元化.
背景情况:
- E2A是一种螺旋环螺旋 (HLH) 转录因子,对细胞分化至关重要.
- HLH蛋白的二分化状态会影响它们的DNA结合和功能.
- 以前对E2A法规的理解缺乏关于其特定的二元化机制的细节.
研究的目的:
- 为了研究纯化的E2A HLH蛋白的二分化特性.
- 阐明二硫化物键在E2A同极体的形成和功能中的作用.
- 了解E2A二分化在不同细胞类型 (B细胞与肌肉细胞) 中是如何调节的.
主要方法:
- 净化E2A螺旋环螺旋 (HLH) 蛋白质.
- 使用对二硫化键敏感的技术分析蛋白质二分化.
- 局部导向的突变发生来破坏二硫化物键的形成.
- 用Id和MyoD评估DNA结合和异构化的试验.
- 在B细胞和肌肉细胞溶解物中E2A二分化的比较.
主要成果:
- 纯化的E2A HLH蛋白自发地形成与二硫化物结合的同型分子,结合DNA.
- 在生理温度下,二硫化键的减少或突变发生有利于单体E2A.
- E2A单体有效地与Id和MyoD异构,但不结合DNA.
- 在B细胞中发现与二硫化物结合的E2A同极体,而在肌肉细胞中只检测到异极体.
结论:
- 对E2A转录因子的一种新的调节机制涉及可逆的二硫化物键形成.
- 这种机制控制了DNA结合的同位体和非DNA结合的异位体之间的切换.
- 细胞类型对E2A二分化状态的特定调节会影响其转录活性.
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