Mackay Hannah L, Stone Helen R, Ronson George E, Ellis Katherine, Lanz Alexander, Aghabi Yara, Walker Alexandra K, Starowicz Katarzyna, Garvin Alexander J, Van Eijk Patrick, Koestler Stefan A, Anthony Elizabeth J, Piberger Ann Liza, Chauhan Anoop S, Conway-Thomas Poppy, Vaitsiankova Alina, Vijayendran Sobana, Beesley James F, Petermann Eva, Brown Eric J, Densham Ruth M, Reed Simon H, Dobbs Felix, Saponaro Marco, Morris Joanna R
Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
CCTT-C Cancer Research UK, Clinical trials unit, Sir Robert Aitken building, College of Medicine and Health, University of Birmingham, Birmingham, B15 2TT, UK.
Nat Commun. 2024 Sep 16;15(1):8102. doi: 10.1038/s41467-024-52250-4.
Mammalian DNA replication relies on various DNA helicase and nuclease activities to ensure accurate genetic duplication, but how different helicase and nuclease activities are properly directed remains unclear. Here, we identify the ubiquitin-specific protease, USP50, as a chromatin-associated protein required to promote ongoing replication, fork restart, telomere maintenance, cellular survival following hydroxyurea or pyridostatin treatment, and suppression of DNA breaks near GC-rich sequences. We find that USP50 supports proper WRN-FEN1 localisation at or near stalled replication forks. Nascent DNA in cells lacking USP50 shows increased association of the DNA2 nuclease and RECQL4 and RECQL5 helicases and replication defects in cells lacking USP50, or FEN1 are driven by these proteins. Consequently, suppression of DNA2 or RECQL4/5 improves USP50-depleted cell resistance to agents inducing replicative stress and restores telomere stability. These data define an unexpected regulatory protein that promotes the balance of helicase and nuclease use at ongoing and stalled replication forks.
哺乳动物的DNA复制依赖于多种DNA解旋酶和核酸酶活性，以确保准确的基因复制，但不同的解旋酶和核酸酶活性如何被正确引导仍不清楚。在这里，我们鉴定出泛素特异性蛋白酶USP50是一种与染色质相关的蛋白质，它是促进正在进行的复制、叉形重启、端粒维持、羟基脲或吡啶抑素处理后的细胞存活以及抑制富含GC序列附近的DNA断裂所必需的。我们发现USP50支持WRN-FEN1在停滞的复制叉处或其附近的正确定位。缺乏USP50的细胞中的新生DNA显示DNA2核酸酶以及RECQL4和RECQL5解旋酶的结合增加，并且缺乏USP50或FEN1的细胞中的复制缺陷是由这些蛋白质驱动的。因此，抑制DNA2或RECQL4/5可提高USP50缺失细胞对诱导复制应激的试剂的抗性，并恢复端粒稳定性。这些数据定义了一种意想不到的调节蛋白，它促进了正在进行的和停滞的复制叉处解旋酶和核酸酶使用的平衡。
