Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Korea.
FEBS J. 2014 Nov;281(21):4841-51. doi: 10.1111/febs.13022. Epub 2014 Sep 19.
The Edc3 protein is an enhancer of mRNA decapping, and acts as a scaffold protein for the mRNA granules that are known as processing bodies in yeast. In the pathogenic yeast Candida albicans, various stresses, such as glucose depletion, oxidative stress, and filamentation defects, induce the accumulation of processing bodies. Here, we report that the edc3/edc3 deletion strain showed increased resistance to various stresses, including hydrogen peroxide, acetic acid, and high temperature. Oxidative stress is known to induce the intracellular accumulation of reactive oxygen species (ROS) and apoptotic cell death in C. albicans. We found that the ROS level was lower in edc3/edc3 cells than in wild-type cells following oxidative stress. We also observed that expression of the metacaspase gene CaMCA1 was decreased in edc3/edc3 cells. Overexpression of CaMCA1 suppressed the decreased accumulation of ROS and the increased resistance to hydrogen peroxide in edc3/edc3 cells. The catalase Cat1 and the superoxide dismutase Sod1 were upregulated in edc3/edc3 cells as compared with wild-type cells. On the basis of these findings, we suggest that EDC3 plays a critical role in the expression of CaMCA1 and the oxidative stress response in C. albicans.
Edc3 蛋白是 mRNA 去帽的增强子，作为 mRNA 颗粒的支架蛋白，这些颗粒在酵母中被称为处理体。在致病性酵母白色念珠菌中，各种应激，如葡萄糖耗竭、氧化应激和丝状缺陷，会诱导处理体的积累。在这里，我们报告说，edc3/edc3 缺失菌株对各种应激，包括过氧化氢、乙酸和高温，表现出更高的抗性。氧化应激已知会诱导白色念珠菌细胞内活性氧（ROS）的积累和细胞凋亡。我们发现，在氧化应激后，edc3/edc3 细胞中的 ROS 水平低于野生型细胞。我们还观察到，edc3/edc3 细胞中 metacaspase 基因 CaMCA1 的表达降低。CaMCA1 的过表达抑制了 edc3/edc3 细胞中 ROS 积累的减少和对过氧化氢的抗性增加。与野生型细胞相比，edc3/edc3 细胞中过氧化氢酶 Cat1 和超氧化物歧化酶 Sod1 的表达上调。基于这些发现，我们认为 EDC3 在白色念珠菌中 CaMCA1 的表达和氧化应激反应中起着关键作用。
