Khoury Chamel M, Yang Zhao, Li Xiao Yu, Vignali Marissa, Fields Stanley, Greenwood Michael T
Department of Medicine, McGill University, Montreal, Quebec, Canada.
FEMS Yeast Res. 2008 Jun;8(4):540-63. doi: 10.1111/j.1567-1364.2008.00367.x. Epub 2008 Mar 18.
The apoptotic programme is evolutionarily conserved between yeast and metazoan organisms. We have previously identified a number of mammalian cDNAs capable of suppressing the deleterious effects of Bax expression in yeast. We herein report that one such suppressor, named Tsc22((86)), represents the C-terminal 86 amino acids of the previously characterized leucine zipper (LZ) motif-containing transcriptional regulator Tsc22. Employing a genome-wide two-hybrid screen, functional genomics, and deletion mutagenesis approaches, we conclude that Tsc22((86))-mediated antiapoptosis is independent of the LZ motif and is likely independent of effects on gene transcription. Rather, a 16-residue sequence within the conserved 56-residue TSC22 domain is necessary for antiapoptosis. The presence of a similar sequence was used to predict an antiapoptotic role for two yeast proteins, Sno1p and Fyv10p. Overexpression and knock-out experiments were used to validate this prediction. These findings demonstrate the potential of studying heterologous proteins in yeast to uncover novel biological insights into the regulation of apoptosis.
凋亡程序在酵母和后生动物之间具有进化保守性。我们之前已经鉴定出一些能够抑制酵母中Bax表达有害效应的哺乳动物cDNA。我们在此报告，一种名为Tsc22((86))的抑制因子代表了先前鉴定的含亮氨酸拉链（LZ）基序的转录调节因子Tsc22的C末端86个氨基酸。通过全基因组双杂交筛选、功能基因组学和缺失诱变方法，我们得出结论，Tsc22((86))介导的抗凋亡作用独立于LZ基序，并且可能独立于对基因转录的影响。相反，保守的56个氨基酸的TSC22结构域内的一个16个残基的序列对于抗凋亡是必需的。利用相似序列的存在预测了两种酵母蛋白Sno1p和Fyv10p的抗凋亡作用。通过过表达和敲除实验验证了这一预测。这些发现证明了在酵母中研究异源蛋白以揭示凋亡调控新生物学见解的潜力。
