McGillivary Rebecca M, Sood Pranidhi, Hammar Katherine, Marshall Wallace F
Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
Central Microscopy Facility, Marine Biological Laboratory, Woods Hole, MA, USA.
iScience. 2023 Jul 10;26(8):107318. doi: 10.1016/j.isci.2023.107318. eCollection 2023 Aug 18.
provides a unique opportunity to study how cells regulate nuclear shape because its macronucleus undergoes a rapid, dramatic, and developmentally regulated shape change. We found that the volume of the macronucleus increases during coalescence, suggesting an inflation-based mechanism. When the nuclear transport factor, CSE1, is knocked down by RNAi, the shape and volume changes of the macronucleus are attenuated, and nuclear morphology is altered. CSE1 protein undergoes a dynamic relocalization correlated with nuclear shape changes, being mainly cytoplasmic prior to nuclear coalescence, and accumulating inside the macronucleus during coalescence. At the end of regeneration, CSE1 protein levels are reduced as the macronucleus returns to its pre-coalescence volume. We propose a model in which nuclear transport via CSE1 is required to increase the volume of the macronucleus, thereby decreasing the surface-to-volume ratio and driving coalescence of the nodes into a single mass.
提供了一个独特的机会来研究细胞如何调节核形状，因为其大核会经历快速、显著且受发育调控的形状变化。我们发现，在融合过程中，大核的体积会增加，这表明存在一种基于膨胀的机制。当通过RNA干扰敲低核转运因子CSE1时，大核的形状和体积变化会减弱，并且核形态会改变。CSE1蛋白会发生动态重新定位，与核形状变化相关，在核融合之前主要位于细胞质中，在融合过程中积累在大核内部。在再生结束时，随着大核恢复到融合前的体积，CSE1蛋白水平会降低。我们提出了一个模型，其中通过CSE1进行的核转运是增加大核体积所必需的，从而降低表面积与体积比，并促使节点融合成一个单一的团块。
