@misc{oai:repo.qst.go.jp:00071116,
 author = {Tsukamoto, Satoshi and et.al and 塚本 智史},
 month = {May},
 note = {In most animal species, transformation of the highly differentiated oocyte to the totipotent embryo after fertilization, a process known as oocyte-to-embryo transition, is essential for further embryonic development. During the transition, maternal factors including mRNA, protein, and organelles that are stored during oogenesis are rapidly degraded and products are newly synthesized. Induction of a bulk degradation pathway would therefore be an ideal way to eliminate these maternal factors and recycle them to synthesize new products. Autophagy is a cytoplasmic bulk degradation pathway, in which the cytoplasmic contents sequestered by autophagosomes are delivered to lysosomes for degradation by lysosomal hydrolases. In this study, we successfully imaged autophagic activity in developing embryos by monitoring the fluorescence protein degradation during preimplantation development. We microinjected mRNA encoding GFP-LC3, an autophagosome marker, into 1-cell embryos and observed its fluorescence under live cell conditions. The fluorescence level of GFP-LC3 was constantly high at the 2-cell stage, but was significantly decreased between the 4- to 8-cell stage. We confirmed that GFP-LC3 degradation was completely blocked by treatment with bafilomycin A1, a specific inhibitor of vacuolar H+ ATPase, which caused the lysosomal pH to increase, indicating that GFP-LC3 degradation is dependent on both autophagic activation and lysosomal acidification. Using our monitoring system, we also investigated whether autophagic activity decreased in aged embryos and found that the level of GFP-LC3 degradation declined with age, probably due to decreased lysosomal activity. The developed method was able to monitor autophagic activity in developing embryos and revealed that autophagic activity decreases in an age-dependent manner., Heavy Ion in Therapy and Space Radiation Spymposium 2013},
 title = {Monitoring of autophagic activity in the developing mouse embryo},
 year = {2013}
}