Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología CSIC, Campus de Cantoblanco-UAM, 28049 Madrid, Spain.
J Cell Sci. 2009 Nov 15;122(Pt 22):4130-40. doi: 10.1242/jcs.052233. Epub 2009 Oct 27.
During induction of the virulence program in the phytopathogenic fungus Ustilago maydis, the cell cycle is arrested on the plant surface and it is not resumed until the fungus enters the plant. The mechanism of this cell cycle arrest is unknown, but it is thought that it is necessary for the correct implementation of the virulence program. Here, we show that this arrest takes place in the G2 phase, as a result of an increase in the inhibitory phosphorylation of the catalytic subunit of the mitotic cyclin-dependent kinase Cdk1. Sequestration in the cytoplasm of the Cdc25 phosphatase seems to be one of the reasons for the increase in inhibitory phosphorylation. Strikingly, we also report the DNA-damage checkpoint kinase Chk1 appears to be involved in this process. Our results support the emerging idea that checkpoint kinases have roles other than in the DNA-damage response, by virtue of their ability to interact with the cell cycle machinery.
在植物病原真菌玉米黑粉菌的毒力程序诱导过程中，细胞周期在植物表面被阻断，直到真菌进入植物后才恢复。这种细胞周期阻断的机制尚不清楚，但人们认为这对于毒力程序的正确实施是必要的。在这里，我们表明这种阻断发生在 G2 期，是由于有丝分裂细胞周期依赖性激酶 Cdk1 的催化亚基的抑制性磷酸化增加所致。Cdc25 磷酸酶在细胞质中的隔离似乎是抑制性磷酸化增加的原因之一。引人注目的是，我们还报告了 DNA 损伤检查点激酶 Chk1 似乎也参与了这一过程。我们的研究结果支持了一个新兴的观点，即检查点激酶通过与细胞周期机制相互作用，除了在 DNA 损伤反应中具有作用外，还具有其他作用。
