Bienko Marzena, Green Catherine M, Crosetto Nicola, Rudolf Fabian, Zapart Grzegorz, Coull Barry, Kannouche Patricia, Wider Gerhard, Peter Matthias, Lehmann Alan R, Hofmann Kay, Dikic Ivan
Institute for Biochemistry II, Goethe University Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
Science. 2005 Dec 16;310(5755):1821-4. doi: 10.1126/science.1120615.
Translesion synthesis (TLS) is the major pathway by which mammalian cells replicate across DNA lesions. Upon DNA damage, ubiquitination of proliferating cell nuclear antigen (PCNA) induces bypass of the lesion by directing the replication machinery into the TLS pathway. Yet, how this modification is recognized and interpreted in the cell remains unclear. Here we describe the identification of two ubiquitin (Ub)-binding domains (UBM and UBZ), which are evolutionarily conserved in all Y-family TLS polymerases (pols). These domains are required for binding of poleta and poliota to ubiquitin, their accumulation in replication factories, and their interaction with monoubiquitinated PCNA. Moreover, the UBZ domain of poleta is essential to efficiently restore a normal response to ultraviolet irradiation in xeroderma pigmentosum variant (XP-V) fibroblasts. Our results indicate that Ub-binding domains of Y-family polymerases play crucial regulatory roles in TLS.
跨损伤合成（TLS）是哺乳动物细胞跨越DNA损伤进行复制的主要途径。DNA损伤时，增殖细胞核抗原（PCNA）的泛素化通过引导复制机制进入TLS途径诱导损伤绕过。然而，这种修饰在细胞中如何被识别和解读仍不清楚。在此，我们描述了两个泛素（Ub）结合结构域（UBM和UBZ）的鉴定，它们在所有Y家族TLS聚合酶（pols）中具有进化保守性。这些结构域是polη和polι与泛素结合、它们在复制工厂中的积累以及它们与单泛素化PCNA相互作用所必需的。此外，polη的UBZ结构域对于在着色性干皮病变异型（XP-V）成纤维细胞中有效恢复对紫外线照射的正常反应至关重要。我们的结果表明，Y家族聚合酶的Ub结合结构域在TLS中发挥关键的调节作用。
