Nemergut M E, Mizzen C A, Stukenberg T, Allis C D, Macara I G
Center for Cell Signaling, University of Virginia, Charlottesville, VA 22908, USA.
Science. 2001 May 25;292(5521):1540-3. doi: 10.1126/science.292.5521.1540.
The Ran guanosine triphosphatase (GTPase) controls nucleocytoplasmic transport, mitotic spindle formation, and nuclear envelope assembly. These functions rely on the association of the Ran-specific exchange factor, RCC1 (regulator of chromosome condensation 1), with chromatin. We find that RCC1 binds directly to mononucleosomes and to histones H2A and H2B. RCC1 utilizes these histones to bind Xenopus sperm chromatin, and the binding of RCC1 to nucleosomes or histones stimulates the catalytic activity of RCC1. We propose that the docking of RCC1 to H2A/H2B establishes the polarity of the Ran-GTP gradient that drives nuclear envelope assembly, nuclear transport, and other nuclear events.
Ran鸟苷三磷酸酶（GTPase）控制核质运输、有丝分裂纺锤体形成和核膜组装。这些功能依赖于Ran特异性交换因子RCC1（染色体凝聚调节因子1）与染色质的结合。我们发现RCC1直接与单核小体以及组蛋白H2A和H2B结合。RCC1利用这些组蛋白与非洲爪蟾精子染色质结合，并且RCC1与核小体或组蛋白的结合会刺激RCC1的催化活性。我们提出RCC1与H2A/H2B的对接建立了驱动核膜组装、核运输及其他核事件的Ran-GTP梯度的极性。
