In vivo analysis of autophagy in response to nutrient starvation using transgenic mice expressing a fluorescent autophagosome marker
In vivo analysis of autophagy in response to nutrient starvation using transgenic mice expressing a fluorescent autophagosome marker
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DOI：
10.1091/mbc.e03-09-0704
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发表时间：
2004-03-01
影响因子：
3.3
通讯作者：
Ohsumi, Y
中科院分区：
文献类型：
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作者：
Mizushima, N;Yamamoto, A;Ohsumi, Y
巨自噬介导了细胞质成分的整体降解。它解释了大多数长寿蛋白质的降解：细胞质成分，包括细胞器，被隔离到自噬小体中，自噬小体随后与溶酶体融合，在那里发生降解。虽然自噬可能参与动态平衡、发育、细胞死亡和发病机制，但由于监测方法的限制，尚未对哺乳动物进行系统的活体分析。为了了解自噬在体内发生的地点和时间，我们建立了系统表达GFP的转基因小鼠，融合到LC3，这是酵母Atg8(Aut7/Apg8)的哺乳动物同源物，并作为自噬的标记蛋白。荧光显微镜分析表明，在大多数组织中，营养饥饿以不同的方式诱导自噬。在一些组织中，自噬甚至在没有饥饿处理的情况下活跃地发生。我们的结果表明，自噬的调节是器官依赖的，自噬的作用并不局限于饥饿反应。这种转基因小鼠模型是研究哺乳动物自噬的有用工具。
Macroautophagy mediates the bulk degradation of cytoplasmic components. It accounts for the degradation of most long-lived proteins: cytoplasmic constituents, including organelles, are sequestered into autophagosomes, which subsequently fuse with lysosomes, where degradation occurs. Although the possible involvement of autophagy in homeostasis, development, cell death, and pathogenesis has been repeatedly pointed out, systematic in vivo analysis has not been performed in mammals, mainly because of a limitation of monitoring methods. To understand where and when autophagy occurs in vivo, we have generated transgenic mice systemically expressing GFP fused to LC3, which is a mammalian homologue of yeast Atg8 (Aut7/Apg8) and serves as a marker protein for autophagosomes. Fluorescence microscopic analyses revealed that autophagy is differently induced by nutrient starvation in most tissues. In some tissues, autophagy even occurs actively without starvation treatments. Our results suggest that the regulation of autophagy is organ dependent and the role of autophagy is not restricted to the starvation response. This transgenic mouse model is a useful tool to study mammalian autophagy.