Activation of the DNA damage checkpoint in yeast lacking the histone chaperone anti-silencing function 1
Activation of the DNA damage checkpoint in yeast lacking the histone chaperone anti-silencing function 1
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DOI：
10.1128/mcb.24.23.10313-10327.2004
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发表时间：
2004-12-01
影响因子：
5.3
通讯作者：
Tyler, JK
中科院分区：
文献类型：
--
作者：
Ramey, CJ;Howar, S;Tyler, JK
将真核生物基因组包装成染色质可能对维持基因组完整性很重要。染色质结构通过包括抗沉默功能1 （ASF1）在内的染色质组装因子的作用组装到新合成的DNA上。为了研究染色质结构在维持基因组完整性中的作用，我们检测了缺乏组蛋白伴侣Asf1p的出芽酵母。我们发现，由于DNA损伤检查点的激活，缺乏Asf1p的酵母在细胞周期中期积累。此外，缺乏Asf1p的酵母对DNA聚合酶α突变和DNA复制应激高度敏感。虽然缺乏Asf1p的酵母菌可以完成DNA复制，但它们在DNA复制过程中发生的DNA损伤率大大提高，正如自发的dc2p-绿色荧光蛋白灶所表明的那样。asf1突变体中自发DNA损伤水平升高是由于DNA损伤增加，而不是由于无法修复双链DNA断裂，因为asf1突变体具有完全的双链DNA修复功能。我们的数据表明，asf1突变体中染色质结构的改变导致DNA复制过程中自发重组、突变和DNA损伤灶形成的速率升高，这反过来又激活了响应DNA损伤的细胞周期检查点。
The packaging of the eukaryotic genome into chromatin is likely to be important for the maintenance of genomic integrity. Chromatin structures are assembled onto newly synthesized DNA by the action of chromatin assembly factors, including anti-silencing function 1 (ASF1). To investigate the role of chromatin structure in the maintenance of genomic integrity, we examined budding yeast lacking the histone chaperone Asf1p. We found that yeast lacking Asf1p accumulate in metaphase of the cell cycle due to activation of the DNA damage checkpoint. Furthermore, yeast lacking Asf1p are highly sensitive to mutations in DNA polymerase alpha and to DNA replicational stresses. Although yeast lacking Asf1p do complete DNA replication, they have greatly elevated rates of DNA damage occurring during DNA replication, as indicated by spontaneous Ddc2p-green fluorescent protein foci. The presence of elevated levels of spontaneous DNA damage in asf1 mutants is due to increased DNA damage, rather than the failure to repair double-strand DNA breaks, because asf1 mutants are fully functional for double-strand DNA repair. Our data indicate that the altered chromatin structure in asf1 mutants leads to elevated rates of spontaneous recombination, mutation, and DNA damage foci formation arising during DNA replication, which in turn activates cell cycle checkpoints that respond to DNA damage.