Laboratory of Cell Cycles of Algae, Centre Algatech, Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czech Republic.
Cells. 2019 Jul 17;8(7):735. doi: 10.3390/cells8070735.
DNA damage is a ubiquitous threat endangering DNA integrity in all living organisms. Responses to DNA damage include, among others, induction of DNA repair and blocking of cell cycle progression in order to prevent transmission of damaged DNA to daughter cells. Here, we tested the effect of the antibiotic zeocin, inducing double stranded DNA breaks, on the cell cycle of synchronized cultures of the green alga . After zeocin application, DNA replication partially occurred but nuclear and cellular divisions were completely blocked. Application of zeocin combined with caffeine, known to alleviate DNA checkpoints, decreased cell viability significantly. This was probably caused by a partial overcoming of the cell cycle progression block in such cells, leading to aberrant cell divisions. The cell cycle block was accompanied by high steady state levels of mitotic cyclin-dependent kinase activity. The data indicate that DNA damage response in is connected to the cell cycle block, accompanied by increased and stabilized mitotic cyclin-dependent kinase activity.
DNA 损伤是一种普遍存在的威胁，危及所有生物体内的 DNA 完整性。对 DNA 损伤的反应包括诱导 DNA 修复和阻止细胞周期进程，以防止受损 DNA 传递给子细胞。在这里，我们测试了抗生素博来霉素（zeocin）的作用，博来霉素诱导双链 DNA 断裂，对同步培养的绿藻的细胞周期的影响。博来霉素处理后，DNA 复制部分发生，但核和细胞分裂完全被阻断。与咖啡因（已知可缓解 DNA 检验点）联合应用博来霉素，显著降低细胞活力。这可能是由于部分克服了这种细胞的细胞周期进展受阻，导致异常的细胞分裂。细胞周期阻滞伴随着有丝分裂周期蛋白依赖性激酶活性的高水平稳定状态。数据表明，的 DNA 损伤反应与细胞周期阻滞有关，伴随着有丝分裂周期蛋白依赖性激酶活性的增加和稳定。
