De Smet Kris, Eberhardt Ines, Reekmans Rieka, Contreras Roland
Fundamental and Applied Molecular Biology, Department for Molecular Biomedical Research, Ghent University and VIB, Technologiepark 927, B-9052 Gent, Belgium.
Yeast. 2004 Dec;21(16):1325-34. doi: 10.1002/yea.1180.
Bax is a pro-apoptotic member of the Bcl-2 family of proteins involved in the regulation of genetically programmed cell death in mammalian cells. It has been shown that heterologous expression of Bax in several yeast species, such as Saccharomyces cerevisiae, Schizosaccharomyces pombe and Pichia pastoris, also induces cell death. In this study we investigated the effects of Bax expression in the pathogenic yeast Candida albicans. Cell death inducing expression of Bax required a synthetic BAX gene that was codon-optimized for expression in Candida albicans. Expression of this BAX gene resulted in growth inhibition and cell death. By fusing Bax with the yeast enhanced green fluorescent protein of Aequoria victoria, the cell death-inducing effect of Bax was increased due to reduced proteolytic degradation of Bax. Using this fusion protein we showed that, upon expression in C. albicans, Bax co-localizes with the mitochondria. Furthermore, we showed for the first time that expression of Bax in yeast causes the mitochondria, which are normally distributed throughout the cell, to cluster in the perinuclear region.
Bax是Bcl-2蛋白家族的促凋亡成员，参与哺乳动物细胞中基因程序性细胞死亡的调控。研究表明，Bax在几种酵母物种（如酿酒酵母、粟酒裂殖酵母和巴斯德毕赤酵母）中的异源表达也会诱导细胞死亡。在本研究中，我们调查了Bax在致病性酵母白色念珠菌中的表达效果。诱导细胞死亡的Bax表达需要一个经过密码子优化以在白色念珠菌中表达的合成BAX基因。该BAX基因的表达导致生长抑制和细胞死亡。通过将Bax与维多利亚水母的酵母增强绿色荧光蛋白融合，由于Bax蛋白水解降解减少，Bax的细胞死亡诱导作用增强。利用这种融合蛋白，我们发现，在白色念珠菌中表达时，Bax与线粒体共定位。此外，我们首次表明，酵母中Bax的表达会导致通常分布在整个细胞中的线粒体聚集在核周区域。
