Jajoo Rishi, Jung Yoonseok, Huh Dann, Viana Matheus P, Rafelski Susanne M, Springer Michael, Paulsson Johan
Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA.
Science. 2016 Jan 8;351(6269):169-72. doi: 10.1126/science.aaa8714.
All cellular materials are partitioned between daughters at cell division, but by various mechanisms and with different accuracy. In the yeast Schizosaccharomyces pombe, the mitochondria are pushed to the cell poles by the spindle. We found that mitochondria spatially reequilibrate just before division, and that the mitochondrial volume and DNA-containing nucleoids instead segregate in proportion to the cytoplasm inherited by each daughter. However, nucleoid partitioning errors are suppressed by control at two levels: Mitochondrial volume is actively distributed throughout a cell, and nucleoids are spaced out in semiregular arrays within mitochondria. During the cell cycle, both mitochondria and nucleoids appear to be produced without feedback, creating a net control of fluctuations that is just accurate enough to avoid substantial growth defects.
在细胞分裂时，所有细胞物质都会在子代细胞之间进行分配，但分配机制各异，准确性也不尽相同。在裂殖酵母中，线粒体被纺锤体推至细胞两极。我们发现，线粒体在分裂前会在空间上重新达到平衡，并且线粒体体积和含DNA的类核反而会根据每个子代细胞继承的细胞质比例进行分离。然而，类核分配错误会在两个层面受到调控：线粒体体积会在整个细胞中主动分布，类核则在线粒体内以半规则阵列排列。在细胞周期中，线粒体和类核似乎都是在没有反馈的情况下产生的，从而对波动进行净调控，其精确程度刚好足以避免严重的生长缺陷。
