PCNA ubiquitination and REV1 define temporally distinct mechanisms for controlling translesion synthesis in the avian cell line DT40
PCNA ubiquitination and REV1 define temporally distinct mechanisms for controlling translesion synthesis in the avian cell line DT40
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DOI：
10.1016/j.molcel.2008.03.024
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发表时间：
2008-05-23
期刊：
影响因子：
16
通讯作者：
Sale, Julian E.
中科院分区：
文献类型：
--
作者：
Edmunds, Charlotte E.;Simpson, Laura J.;Sale, Julian E.
翻译合成（TLS）是一种潜在的诱变方法，可以绕过复制过程中遇到的DNA损伤，这种损伤需要招募专门的DNA聚合酶来阻止复制分叉或复制后间隙。目前的模型表明，TLS是由DNA滑动钳PCNA的单泛素化激活的。然而，在高等生物中，完全有效的TLS还需要Y家族聚合酶REV1的非催化功能。利用遗传易感的鸡细胞系DT40，我们发现停滞复制分叉处的TLS需要REV1 C端翻译聚合酶相互作用域和泛素结合域都是完整的。然而，令人惊讶的是，PCNA泛素化并不是维持受损DNA正常分叉进程所必需的。相反，PCNA泛素化对于填补增殖后的空白是必不可少的。因此，PCNA泛素化和REV1在DNA损伤旁路的协调中发挥着不同的作用，这些DNA损伤旁路相对于复制叉的捕获而暂时分离。
Translesion synthesis (TLS) is a potentially mutagenic method of bypassing DNA damage encountered during replication that requires the recruitment of specialized DNA polymerases to stalled replication forks or postreplicative gaps. Current models suggest that TLS is activated by monoubiquitination of the DNA sliding clamp PCNA. However, in higher organisms, fully effective TLS also requires a noncatalytic function of the Y family polymerase REV1. Using the genetically tractable chicken cell line DT40, we show that TLS at stalled replication forks requires that both the translesion polymerase-interaction domain and ubiquitin-binding domain in the C terminus of REV1 are intact. Surprisingly, however, PCNA ubiquitination is not required to maintain normal fork progression on damaged DNA. Conversely, PCNA ubiquitination is essential for filling postreplicative gaps. Thus, PCNA ubiquitination and REV1 play distinct roles in the coordination of DNA damage bypass that are temporally separated relative to replication fork arrest.