Department of Biology, Miyagi University of Education, Sendai, Miyagi, Japan.
Mol Reprod Dev. 2011 Oct-Nov;78(10-11):708-25. doi: 10.1002/mrd.21346. Epub 2011 Jul 19.
During maturation, oocytes must undergo a process of nuclear disassembly, or "germinal vesicle breakdown" (GVBD), that is regulated by signaling pathways involving cyclic AMP (cAMP). In vertebrate and starfish oocytes, cAMP elevation typically prevents GVBD. Alternatively, increased concentrations of intra-oocytic cAMP trigger, rather than inhibit, GVBD in several groups of marine invertebrates. To integrate what is known about the stimulation of GVBD by intra-oocytic cAMP, this article reviews published data for ascidian, bivalve, brittle star, jellyfish, and nemertean oocytes. The bulk of the review concentrates on the three most intensively analyzed groups known to display cAMP-induced GVBD-nemerteans, ascidians, and jellyfish. In addition, this synopsis also presents some previously unpublished findings regarding the stimulatory effects of intra-oocytic cAMP on GVBD in jellyfish and the annelid worm Pseudopotamilla occelata. Finally, factors that may account for the currently known distribution of cAMP-induced GVBD across animal groups are discussed.
在成熟过程中，卵母细胞必须经历核解体过程，即“卵母细胞核破裂”（GVBD），该过程受涉及环腺苷酸（cAMP）的信号通路调节。在脊椎动物和海星卵母细胞中，cAMP 升高通常会阻止 GVBD。相反，几种海洋无脊椎动物卵内 cAMP 浓度的增加会引发 GVBD，而不是抑制 GVBD。为了整合已知的卵内 cAMP 对 GVBD 的刺激作用，本文综述了已发表的关于海鞘、双壳类、海胆、水母和纽形动物卵母细胞的数据。综述的大部分内容集中在三个分析最深入的组，已知显示 cAMP 诱导的 GVBD-纽形动物、海鞘和水母。此外，本概要还介绍了一些关于水母和环节蠕虫 Pseudopotamilla occelata 中卵内 cAMP 对 GVBD 的刺激作用的先前未发表的发现。最后，讨论了可能导致目前已知 cAMP 诱导的 GVBD 在动物群中分布的因素。
