The spd-2 gene is required for polarization of the anteroposterior axis and formation of the sperm asters in the Caenorhabditis elegans zygote
The spd-2 gene is required for polarization of the anteroposterior axis and formation of the sperm asters in the Caenorhabditis elegans zygote
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DOI：
10.1006/dbio.2000.9714
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发表时间：
2000-06-01
影响因子：
2.7
通讯作者：
White, JG
中科院分区：
文献类型：
--
作者：
O'Connell, KF;Maxwell, KN;White, JG
在秀丽隐杆线虫受精卵中，前后（AP）轴的极化发生在受精后的短暂重组期间，并导致离散的细胞质和皮质结构域的建立。在细胞质中，种系颗粒或P颗粒通过肌动球蛋白驱动的细胞质喷泉循环，并定位于后部，而在皮质中，AP极性所需的两种蛋白质，即PAR-2和PAR-3，分别定位于后部和前部。确定AP轴方向的位置线索的身份是未知的，虽然它已被假定为精子原核/中心体复合体（SPCC）的组成部分，因为SPCC的位置与AP轴的方向和喷泉流的方向相关。在这里，我们表明，突变的spd-e基因破坏极化的AP轴。在突变合子，喷泉现在的细胞质和相关的不对称皮质收缩是缺席的，P颗粒不本地化，和皮质PAR-3不会成为不对称分布。有趣的是，皮质PAR-2随机定位于两极或两极。PAR-2的随机定位需要PAR-3，并且表明spd-g依赖性机制通常调节PAR-2/PAR-3相互作用以将PAR-P正确定位在后部。sgd-2突变还通过延迟和减弱精星的形成直到重组期之后来破坏SPCC的形成，这表明spd-e突变破坏了位置线索的形成。我们的研究结果还表明，精星是不是必不可少的原核迁移，但所需的快速女性原核运动和有丝分裂前定位的原核。(C)北京大学出版社.
In the Caenorhabditis elegans zygote, polarization of the anteroposterior (AP) axis occurs during a brief period of reorganization that follows fertilization and results in the establishment of discrete cytoplasmic and cortical domains. In the cytoplasm, germ-line or P granules are circulated by an actomyosin-driven fountain now of cytoplasm and localize to the posterior, while in the cortex, two proteins required for AP polarity, PAR-2 and PAR-3, localize to the posterior and the anterior, respectively. The identity of the positional cue that determines AP axis orientation is not known, although it has been postulated to be a component of the sperm pronucleus/centrosome complex (SPCC) as the position of the SPCC correlates with the orientation of the AP axis and the direction of the fountain flows. Here, we show that mutations in the spd-e gene disrupt polarization of the AP axis. In mutant zygotes, the fountain now of cytoplasm and associated asymmetric cortical contractions are absent, P granules do not localize, and cortical PAR-3 does not become asymmetrically distributed. Interestingly, cortical PAR-2 localizes randomly to either or both poles. The random positioning of PAR-2 requires PAR-3 and indicates that a spd-g-dependent mechanism normally modulates PAR-2/PAR-3 interactions to correctly position PAR-P at the posterior. sgd-2 mutations also disrupt formation of the SPCC by delaying and attenuating the formation of sperm asters until after the period of reorganization, suggesting that spd-e mutations disrupt formation of the positional cue. Our results also indicate that sperm asters are not essential for pronuclear migration but are required for rapid female pronuclear movement and premitotic positioning of the pronuclei. (C) 2000 Academic Press.