Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.
Electron Microscope Lab, University of California, Berkeley, Berkeley, United States.
Elife. 2019 Aug 9;8:e47156. doi: 10.7554/eLife.47156.
Production of healthy gametes in meiosis relies on the quality control and proper distribution of both nuclear and cytoplasmic contents. Meiotic differentiation naturally eliminates age-induced cellular damage by an unknown mechanism. Using time-lapse fluorescence microscopy in budding yeast, we found that nuclear senescence factors - including protein aggregates, extrachromosomal ribosomal DNA circles, and abnormal nucleolar material - are sequestered away from chromosomes during meiosis II and subsequently eliminated. A similar sequestration and elimination process occurs for the core subunits of the nuclear pore complex in both young and aged cells. Nuclear envelope remodeling drives the formation of a membranous compartment containing the sequestered material. Importantly, de novo generation of plasma membrane is required for the sequestration event, preventing the inheritance of long-lived nucleoporins and senescence factors into the newly formed gametes. Our study uncovers a new mechanism of nuclear quality control and provides insight into its function in meiotic cellular rejuvenation.
减数分裂中健康配子的产生依赖于核质内容物的质量控制和正确分布。减数分裂自然消除了未知机制引起的年龄相关的细胞损伤。通过在芽殖酵母中使用延时荧光显微镜,我们发现核衰老因子——包括蛋白质聚集体、染色体外核糖体 DNA 环和异常核仁物质——在减数分裂 II 期间被隔离在染色体之外,随后被消除。在年轻和衰老的细胞中,核孔复合物的核心亚基也会发生类似的隔离和消除过程。核膜重塑驱动含有隔离物质的膜结构域的形成。重要的是,质膜的从头生成对于隔离事件是必需的,防止长寿核孔蛋白和衰老因子遗传到新形成的配子中。我们的研究揭示了一种新的核质量控制机制,并为其在减数分裂细胞年轻化中的功能提供了深入了解。