Xiang Zhiming, Qu Fufa, Wang Fuxuan, Xiao Shu, Jun Li, Zhang Yang, Yu Ziniu
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, Guangdong, China.
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, Guangdong, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.
Fish Shellfish Immunol. 2015 Feb;42(2):225-32. doi: 10.1016/j.fsi.2014.11.013. Epub 2014 Nov 20.
Apoptosis has been primarily investigated in mammals, and little is known about apoptosis in mollusks. The proteins Bax and Bak play critical roles in the mitochondrial apoptosis pathway and in determining cell fate. In this study, ChBax and ChBak, homologs of the well-known Bax and Bak proteins, were identified from the oyster Crassostrea hongkongensis. The ChBax/Bak proteins consist of 207/232 amino acids with the typical domains found in BCL-2 family members. ChBax and ChBak mRNA expression were detected in all 8 of the selected oyster tissues and at the different stages of development. Fluorescence microscopy revealed that the full-length proteins of ChBax/Bak were located in the cytoplasm and mitochondrial outer membrane, of HEK293T cells, respectively. Furthermore, both of the genes' expression levels were found to increase in the hemocytes of oysters challenged with pathogens. The over-expression of ChBax or ChBak activates the p53-Luc reporter gene in HEK293T cells in a dose-dependent manner. These results indicate that ChBax and ChBak may play important roles in the mitochondrial apoptotic pathway in oysters.
细胞凋亡主要在哺乳动物中进行了研究，而对于软体动物的细胞凋亡了解甚少。蛋白质Bax和Bak在线粒体凋亡途径以及决定细胞命运方面发挥着关键作用。在本研究中，从香港牡蛎中鉴定出了著名的Bax和Bak蛋白的同源物ChBax和ChBak。ChBax/Bak蛋白由207/232个氨基酸组成，具有BCL-2家族成员中常见的典型结构域。在所选的8种牡蛎组织以及不同发育阶段均检测到了ChBax和ChBak mRNA的表达。荧光显微镜显示，ChBax/Bak的全长蛋白分别位于HEK293T细胞的细胞质和线粒体外膜中。此外，发现这两个基因在受到病原体攻击的牡蛎血细胞中的表达水平均升高。ChBax或ChBak的过表达以剂量依赖的方式激活HEK293T细胞中的p53-Luc报告基因。这些结果表明，ChBax和ChBak可能在牡蛎的线粒体凋亡途径中发挥重要作用。
