Recruitment of phosphorylated chromatin assembly factor 1 to chromatin after UV irradiation of human cells.
Recruitment of phosphorylated chromatin assembly factor 1 to chromatin after UV irradiation of human cells.
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DOI：
10.1083/jcb.143.3.563
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发表时间：
1998-11-02
影响因子：
7.8
通讯作者：
Almouzni, G
中科院分区：
文献类型：
--
作者：
Martini, E;Roche, D M;Marheineke, K;Verreault, A;Almouzni, G
研究了 HeLa 细胞紫外线照射后人染色质组装因子 1 (CAF-1) 的亚细胞分布和翻译后修饰。在异步细胞群中，仅发现两个大 CAF-1 亚基 p150 和 p60 的一个亚级分存在于染色质相关级分中。该部分在未照射细胞的 S 期最为丰富，而在 G2 细胞中则大大减少。紫外线照射后，所有细胞中与染色质相关的 CAF-1 形式均显着增加，无论其在细胞周期中的位置如何。这种染色质募集类似于 PCNA（一种 DNA 复制和修复因子）的募集。在未照射的 G2 细胞中，p60 的染色质相关部分主要低磷酸化。紫外线照射导致 p60 亚基的磷酸化形式快速招募到染色质。此外，与染色质相关的 CAF-1 p60 和 p150 亚基的量是紫外线照射剂量的函数。与这些体内观察一致，我们发现在体外UV光产物修复过程中刺激核小体组装所需的CAF-1的量取决于损伤的数量和CAF-1的磷酸化状态。本文描述的人类细胞紫外线照射后 CAF-1 募集到染色质的过程支持了 CAF-1 在连接染色质组装和 DNA 修复方面的生理作用。
The subcellular distribution and posttranslational modification of human chromatin assembly factor 1 (CAF-1) have been investigated after UV irradiation of HeLa cells. In an asynchronous cell population only a subfraction of the two large CAF-1 subunits, p150 and p60, were found to exist in a chromatin-associated fraction. This fraction is most abundant during S phase in nonirradiated cells and is much reduced in G2 cells. After UV irradiation, the chromatin-associated form of CAF-1 dramatically increased in all cells irrespective of their position in the cell cycle. Such chromatin recruitment resembles that seen for PCNA, a DNA replication and repair factor. The chromatin-associated fraction of p60 was predominantly hypophosphorylated in nonirradiated G2 cells. UV irradiation resulted in the rapid recruitment to chromatin of phosphorylated forms of the p60 subunit. Furthermore, the amount of the p60 and p150 subunits of CAF-1 associated with chromatin was a function of the dose of UV irradiation. Consistent with these in vivo observations, we found that the amount of CAF-1 required to stimulate nucleosome assembly during the repair of UV photoproducts in vitro depended upon both the number of lesions and the phosphorylation state of CAF-1. The recruitment of CAF-1 to chromatin in response to UV irradiation of human cells described here supports a physiological role for CAF-1 in linking chromatin assembly to DNA repair.