State Key Laboratory for Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Sci Rep. 2017 Feb 22;7:43161. doi: 10.1038/srep43161.
Sperm nuclear migration during fertilization in Arabidopsis and rice has recently been found to be actin-dependent, but the driving force behind this actin cytoskeleton-dependent motion is unclear. Here, we confirmed that the actin-dependent sperm nuclei migration during fertilization is a conserved mechanism in plants. Using in vitro fertilization systems, we showed that a functional actin is also essential in maize and tobacco for sperm nuclei migration after gamete membrane fusion. Cytoskeleton depolymerization inhibitor treatments supported the view that sperm nuclei migration is actin-dependent but microtubule-independent in both egg cell and central cell during double fertilization. We further revealed that the actin-based motor myosin is not the driving force for sperm nuclear migration in maize and tobacco. The WASP-Arp2/3 complex signal cascade is shown here to be involved in the regulation of sperm nuclear migration in maize and tobacco. It is interesting that sperm nuclei migration within somatic cell also need WASP-Arp2/3 complex signal cascade and actin, suggesting that the mechanism of sperm nuclear migration is not gamete specific.
在拟南芥和水稻的受精过程中，最近发现精子核的迁移是依赖肌动蛋白的，但这种依赖肌动蛋白细胞骨架的运动的驱动力尚不清楚。在这里，我们证实了受精过程中依赖肌动蛋白的精子核迁移是植物中一种保守的机制。通过体外受精系统，我们表明在玉米和烟草中，配子膜融合后精子核迁移也需要功能性肌动蛋白。细胞骨架解聚抑制剂处理支持了这样的观点，即在双受精过程中，卵母细胞和中央细胞中的精子核迁移是依赖肌动蛋白但不依赖微管的。我们进一步揭示，基于肌动蛋白的运动蛋白肌球蛋白不是玉米和烟草中精子核迁移的驱动力。这里显示，WASP-Arp2/3 复合物信号级联参与了玉米和烟草中精子核迁移的调节。有趣的是，体细胞内的精子核迁移也需要 WASP-Arp2/3 复合物信号级联和肌动蛋白，这表明精子核迁移的机制不是配子特异性的。
