Ultrastructural analysis of the autophagic process in yeast: detection of autophagosomes and their characterization.
Ultrastructural analysis of the autophagic process in yeast: detection of autophagosomes and their characterization.
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酵母自噬过程的超微结构分析：自噬体的检测及其表征。
DOI：
10.1083/jcb.124.6.903
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发表时间：
1994-03
影响因子：
7.8
通讯作者：
Ohsumi, Y
中科院分区：
文献类型：
--
作者：
Baba, M;Takeshige, K;Baba, N;Ohsumi, Y
在营养缺乏的条件下，酵母S。酿酒酵母以“自噬体”的形式将其自身的细胞质组分隔离到液泡中（Takeshige，K.，M. Baba，S. Tsuboi，T. Noda和Y.大隅1992. 119：301-311）。免疫电子显微镜显示，两个胞质标记酶，乙醇脱氢酶和磷酸甘油酸激酶，存在于自噬体中的细胞质中的相同的密度，但不存在于空泡汁液，这表明细胞质酶也采取了进入自噬体。为了理解这一过程，我们进行了形态学分析，透射和免疫电子显微镜使用冷冻替代固定方法。当细胞转移到营养饥饿培养基中时，在蛋白酶缺陷突变体细胞的液泡附近发现了完全封闭在双膜中的球形结构。它们的大小、膜厚度和双膜结构的含量与自噬体的结构一致.有时这些双膜结构被发现与液泡膜接触。此外，它们的外膜偶尔被视为连续的液泡膜。碳水化合物的组织化学染色强烈地表明，双膜结构与空泡融合。这些结果表明，这些结构是自噬体的前体，“自噬体”在酵母中。所有获得的数据表明，酵母中的自噬过程基本上类似于哺乳动物细胞中的溶酶体系统。
Under nutrient-deficient conditions, the yeast S. cerevisiae sequesters its own cytoplasmic components into vacuoles in the form of "autophagic bodies" (Takeshige, K., M. Baba, S. Tsuboi, T. Noda, and Y. Ohsumi. 1992. J. Cell Biol. 119:301-311). Immunoelectron microscopy showed that two cytosolic marker enzymes, alcohol dehydrogenase and phosphoglycerate kinase, are present in the autophagic bodies at the same densities as in the cytosol, but are not present in vacuolar sap, suggesting that cytosolic enzymes are also taken up into the autophagic bodies. To understand this process, we performed morphological analyses by transmission and immunological electron microscopies using a freeze- substitution fixation method. Spherical structures completely enclosed in a double membrane were found near the vacuoles of protease-deficient mutant cells when the cells were shifted to nutrient-starvation media. Their size, membrane thickness, and contents of double membrane- structures corresponded well with those of autophagic bodies. Sometimes these double membrane structures were found to be in contact with the vacuolar membrane. Furthermore their outer membrane was occasionally seen to be continuous with the vacuolar membrane. Histochemical staining of carbohydrate strongly suggested that the structures with double membranes fused with the vacuoles. These results indicated that these structures are precursors of autophagic bodies, "autophagosomes" in yeast. All the data obtained suggested that the autophagic process in yeast is essentially similar to that of the lysosomal system in mammalian cells.