Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan.
Electron Microscope Section, Technology Advancement Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan.
Curr Microbiol. 2024 Aug 20;81(10):315. doi: 10.1007/s00284-024-03838-y.
We previously reported autophagy-mediated degradation of nuclei, nucleophagy, in the filamentous fungus Aspergillus oryzae. In this study, we examined whether nuclei are degraded as a whole. We generated A. oryzae mutants deleted for orthologs of Saccharomyces cerevisiae YPT7 and ATG15 which are required, respectively, for autophagosome-vacuole fusion and vacuolar degradation of autophagic bodies. Degradation of histone H2B-EGFP under starvation conditions was greatly decreased in the ΔAoypt7 and ΔAoatg15 mutants. Fluorescence and electron microscopic observations showed that autophagosomes and autophagic bodies surrounding the entire nuclei were accumulated in the cytoplasm of ΔAoypt7 and the vacuole of ΔAoatg15, respectively. These results indicate that nuclei are engulfed in the autophagosomes as a whole and transported/released into the vacuolar lumen where they are degraded.
我们之前曾报道过丝状真菌米曲霉中自噬介导的核降解，即核噬作用。在这项研究中，我们研究了核是否作为一个整体被降解。我们生成了缺失酿酒酵母 YPT7 和 ATG15 同源物的米曲霉突变体，这两个基因分别是自噬体-液泡融合和自噬体空泡降解所必需的。在饥饿条件下，组蛋白 H2B-EGFP 的降解在 ΔAoypt7 和 ΔAoatg15 突变体中大大减少。荧光和电子显微镜观察表明，自噬体和围绕整个核的自噬体分别在 ΔAoypt7 的细胞质中和 ΔAoatg15 的液泡中积累。这些结果表明，核作为一个整体被包裹在自噬体中，并被运输/释放到液泡腔中进行降解。
