Centro Andaluz de Biología del Desarrollo. Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, 41013 Sevilla, Spain.
Centro Andaluz de Biología del Desarrollo. Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas, 41013 Sevilla, Spain.
Cell Rep. 2018 Apr 24;23(4):933-941. doi: 10.1016/j.celrep.2018.03.073.
In metazoans, the nuclear envelope (NE) breakdown (NEBD) occurs during "open" mitosis and meiosis. In the fission yeast Schizosaccharomyces pombe, the mitosis and the first meiotic division (MI) are "closed," during which the NE is maintained. Intriguingly, during the second meiotic division (MII), the NE is also maintained, but nuclear and cytoplasmic molecules are mixed similarly to open mitosis, a phenomenon of unknown biological significance called "virtual" NEBD (vNEBD). Here, we show that importin-α-dependent nucleocytoplasmic transport regulates spindle disassembly late in anaphase B at MI, as previously reported for mitosis. At MII, however, spindle dissolution is triggered by vNEBD early in anaphase B, a mechanism that short-circuits the nucleocytoplasmic transport system. We demonstrate that the sequential action of these two spindle disassembly systems regulates the spatiotemporal order and ploidy of the meiotic products.
在后生动物中，核膜破裂（NEBD）发生在“开放”有丝分裂和减数分裂期间。在裂殖酵母 Schizosaccharomyces pombe 中，有丝分裂和第一次减数分裂（MI）是“封闭的”，在此期间核膜保持完整。有趣的是，在第二次减数分裂（MII）期间，核膜也保持完整，但核和细胞质分子的混合类似于有丝分裂，这种现象的生物学意义尚不清楚，称为“虚拟”核膜破裂（vNEBD）。在这里，我们表明，进口蛋白-α依赖性核质运输调节 MI 后期有丝分裂末期的纺锤体解体，如先前报道的有丝分裂。然而，在 MII 中，vNEBD 在有丝分裂末期早期引发纺锤体解体，这一机制绕过了核质运输系统。我们证明，这两个纺锤体解体系统的顺序作用调节了减数分裂产物的时空顺序和倍性。
