Waksman Institute, Piscataway, NJ 08854, USA.
Adv Exp Med Biol. 2013;757:321-50. doi: 10.1007/978-1-4614-4015-4_11.
Fertilization-the fusion of gametes to produce a new organism-is the culmination of a multitude of intricately regulated cellular processes. In Caenorhabditis elegans, fertilization is highly efficient. Sperm become fertilization competent after undergoing a maturation process during which they become motile, and the plasma membrane protein composition is reorganized in preparation for interaction with the oocyte. The highly specialized gametes begin their interactions by signaling to one another to ensure that fertilization occurs when they meet. The oocyte releases prostaglandin signals to help guide the sperm to the site of fertilization, and sperm secrete a protein called major sperm protein (MSP) to trigger oocyte maturation and ovulation. Upon meeting one another in the spermatheca, the sperm and oocyte fuse in a specific and tightly regulated process. Recent studies are providing new insights into the molecular basis of this fusion process. After fertilization, the oocyte must quickly transition from the relative quiescence of oogenesis to a phase of rapid development during the cleavage divisions of early embryogenesis. In addition, the fertilized oocyte must prevent other sperm from fusing with it as well as produce an eggshell for protection during external development. This chapter will review the nature and regulation of the various cellular processes of fertilization, including the development of fertilization competence, gamete signaling, sperm-oocyte fusion, the oocyte to embryo transition, and production of an eggshell to protect the developing embryo.
受精——配子融合产生新个体——是众多复杂调控细胞过程的高潮。在秀丽隐杆线虫中，受精效率极高。精子在经历成熟过程后获得受精能力，在此过程中它们变得有活力，并且质膜蛋白组成被重新组织，为与卵母细胞相互作用做准备。高度特化的配子通过相互发出信号开始相互作用，以确保在相遇时发生受精。卵母细胞释放前列腺素信号以帮助引导精子到达受精部位，精子分泌一种称为主要精子蛋白（MSP）的蛋白质以触发卵母细胞成熟和排卵。在精囊相遇时，精子和卵母细胞在特定且严格调控的过程中融合。最近的研究为这一融合过程的分子基础提供了新的见解。受精后，卵母细胞必须迅速从卵发生的相对静止状态过渡到早期胚胎发生的卵裂分裂过程中的快速发育阶段。此外，受精卵必须防止其他精子与它融合，并在外部发育过程中产生卵壳以提供保护。本章将综述受精过程中各种细胞过程的性质和调控，包括受精能力的发展、配子信号、精子-卵母细胞融合、卵母细胞到胚胎的转变以及卵壳的产生以保护发育中的胚胎。
