Structural and functional analyses of APG5, a gene involved in autophagy in yeast
Structural and functional analyses of APG5, a gene involved in autophagy in yeast
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DOI：
10.1016/0378-1119(96)00354-x
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发表时间：
1996-10-31
期刊：
影响因子：
3.5
通讯作者：
Ohsumi, Y
中科院分区：
文献类型：
--
作者：
Kametaka, S;Matsuura, A;Ohsumi, Y
通过对酿酒酵母apg5-1突变体自噬缺陷表型的互补，从酵母基因组文库中克隆了酿酒酵母apgs基因。对获得的基因组片段的结构分析表明，APG5基因编码一个由294个氨基酸残基组成的新的亲水性蛋白，与数据库中的其他蛋白没有明显的结构相似性。为了研究其功能，构建了APG5的零等位基因(Delta Apg5)，并将其导入酵母中。DAPG5细胞在营养丰富的条件下正常萌发和生长，但在营养饥饿的情况下，其活力显著下降。它们在自噬方面也有缺陷：在氮饥饿条件下，它们不能将自噬小体隔离在液泡中。这些表型与apg5-1突变体中发现的表型相同。富营养液中缺乏明显的表型，表明APGs功能仅在营养饥饿条件下才需要，但Northern印迹分析表明，在营养耗竭后，其表达水平没有变化。
The APGS gene of Saccharomyces cerevisiae was cloned from a yeast genomic library by complementation of autophagy defective phenotype of apg5-1 mutant. structural analysis of the obtained genomic fragment showed that the APG5 gene encodes a novel hydrophilic protein of 294 amino-acid residues without apparent structural similarities to other proteins in the database. To examine its function, a null allele for APG5 (Delta apg5) was constructed and introduced into yeast. dapg5 cells germinated and grew normally in nutrient-rich condition, however, their viability reduced significantly upon the nutrient starvation. They were also shown to be defective in autophagy: they could not sequester autophagic bodies in the vacuole under nitrogen-starvation conditions. These phenotypes are identical to those found in the apg5-1 mutant. The lack of apparent phenotype in rich medium suggests that APGS function is required only under nutrient starvation condition, however, Northern blot analysis showed that its expression levels remained unchanged after nutrient depletion.