Sun Ling Ling, Li Wan Jie, Wang Hai Tao, Chen Jie, Deng Ping, Wang Yue, Sang Jian Li
Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, People's Republic of China.
Eukaryot Cell. 2011 Nov;10(11):1565-73. doi: 10.1128/EC.05042-11. Epub 2011 Sep 2.
The ability of the pathogenic fungus Candida albicans to switch cellular morphologies is important for infection and virulence. Recent studies have revealed that C. albicans yeast cells can switch to filamentous growth under genotoxic stress in a manner dependent on the DNA replication/damage checkpoint. Here, we have investigated the functions of Pph3 (orf19.4378) and Psy2 (orf19.3685), whose orthologues in Saccharomyces cerevisiae mediate the dephosphorylation of the DNA damage checkpoint kinase Rad53 and the histone variant H2AX during recovery from DNA damage. Deleting PPH3 or PSY2 causes hypersensitivity to DNA-damaging agents, including cisplatin, methylmethane sulfonate (MMS), and UV light. In addition, pph3Δ and psy2Δ cells exhibit strong filamentous growth under genotoxic stress. Flow cytometry analysis shows that the mutant cells have lost the ability to adapt to genotoxic stress and remain arrested even after the stress is withdrawn. Furthermore, we show that Pph3 and Psy2 are required for the dephosphorylation of Rad53, but not H2AX, during DNA damage recovery. Taken together, these results show that C. albicans Pph3 and Psy2 have important roles in mediating genotoxin-induced filamentous growth and regulating Rad53 dephosphorylation.
致病性真菌白色念珠菌转换细胞形态的能力对于感染和毒力至关重要。最近的研究表明，白色念珠菌酵母细胞在遗传毒性应激下能够以依赖于DNA复制/损伤检查点的方式转换为丝状生长。在此，我们研究了Pph3（orf19.4378）和Psy2（orf19.3685）的功能，它们在酿酒酵母中的同源物在从DNA损伤中恢复过程中介导DNA损伤检查点激酶Rad53和组蛋白变体H2AX的去磷酸化。删除PPH3或PSY2会导致对DNA损伤剂（包括顺铂、甲基磺酸甲酯（MMS）和紫外线）敏感。此外，pph3Δ和psy2Δ细胞在遗传毒性应激下表现出强烈的丝状生长。流式细胞术分析表明，突变细胞失去了适应遗传毒性应激的能力，即使在应激消除后仍处于停滞状态。此外，我们表明，在DNA损伤恢复过程中，Pph3和Psy2是Rad53去磷酸化所必需的，但不是H2AX去磷酸化所必需的。综上所述，这些结果表明白色念珠菌Pph3和Psy2在介导基因毒素诱导的丝状生长和调节Rad53去磷酸化方面具有重要作用。
