Live observation of forespore membrane formation in fission yeast
Live observation of forespore membrane formation in fission yeast
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DOI：
10.1091/mbc.e08-04-0414
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发表时间：
2008-08-01
影响因子：
3.3
通讯作者：
Shimoda, Chikashi
中科院分区：
文献类型：
--
作者：
Nakamura, Taro;Asakawa, Haruhiko;Shimoda, Chikashi
裂殖酵母裂殖酵母的孢子形成是一个独特的生物学过程，子细胞的质膜在母细胞的细胞质中重新组装。在减数分裂过程中，一个称为前孢子膜（FSM）的双单位膜被动态地构建。为了获得FSM形成的动态视图，我们通过使用与FSM驻留蛋白Psy1融合的绿色荧光蛋白以及细胞核或微管来可视化活细胞中的FSM。FSM的组装在前期II开始，并且在整个减数分裂II中，细胞中的四个FSM以相同的速率以同步的方式扩增。在减数分裂II完成后，FSM继续扩张，直到闭合形成前孢子，孢子前体。前孢子最初为椭圆形，最终变为球形。在孢子形成缺陷突变体spo3、spo14和spo15中也观察到FSM形成。在spo15突变体中，FSM形成的起始被完全阻断。在spo3突变体中，FSM在早期减数分裂II期间正常扩展，但在晚期和减数分裂后受到严重抑制，而在spo14突变体中，膜扩展在整个减数分裂II期间受到更严重的抑制。这些观察结果表明，FSM扩展由两个步骤组成，减数分裂早期FSM扩展和减数分裂后期和后FSM扩展。探讨了裂殖酵母FSM形成的可能调控机制。
Sporulation in the fission yeast Schizosaccharomyces pombe is a unique biological process in that the plasma membrane of daughter cells is assembled de novo within the mother cell cytoplasm. A double unit membrane called the forespore membrane (FSM) is constructed dynamically during meiosis. To obtain a dynamic view of FSM formation, we visualized FSM in living cells by using green fluorescent protein fused with Psy1, an FSM-resident protein, together with the nucleus or microtubules. The assembly of FSM initiates in prophase II, and four FSMs in a cell expand in a synchronous manner at the same rate throughout meiosis II. After the meiosis II completes, FSMs continue to expand until closure to form the prespore, a spore precursor. Prespores are initially ellipsoidal, and eventually become spheres. FSM formation was also observed in the sporulation-deficient mutants spo3, spo14, and spo15. In the spo15 mutant, the initiation of FSM formation was completely blocked. In the spo3 mutant, the FSM expanded normally during early meiosis II, but it was severely inhibited during late and postmeiosis, whereas in the spo14 mutant, membrane expansion was more severely inhibited throughout meiosis II. These observations suggest that FSM expansion is composed of two steps, early meiotic FSM expansion and late and post meiotic FSM expansion. Possible regulatory mechanisms of FSM formation in fission yeast are discussed.