线虫和哺乳动物精子因子介导的磷脂酶C依赖性Ca2+释放

Phospholipase C-dependent Ca2+ release by worm and mammal sperm factors.

作者信息

Howell Kethurah P, Skipwith Aurelia, Galione Antony, Eckberg William R

机构信息

Department of Biology, Howard University, 415 College Street, NW, Washington, DC 20059-0001, USA.

出版信息

Biochem Biophys Res Commun. 2003 Jul 18;307(1):47-51. doi: 10.1016/s0006-291x(03)01120-3.

DOI:10.1016/s0006-291x(03)01120-3

PMID:12849979

Abstract

Egg activation in all animals evidently requires the synthesis of inositol 1,4,5-trisphosphate (InsP(3)) from phosphatidylinositol 4,5-bisphosphate (PIP(2)) by phospholipase C (PLC). Depending on the organism, InsP(3) elicits either calcium oscillations or a single wave, which in turn initiates development. A soluble component in boar sperm that activates mammalian eggs has been suggested to be a PLC isoform. We tested this hypothesis in vitro using egg microsomes of Chaetopterus. Boar sperm factor elicited Ca(2+) release from the microsomes by an InsP(3)-dependent mechanism. The PLC inhibitor U-73122, but not its inactive analog U-73343, blocked the response to sperm factor but not to InsP(3). U-73122 also inhibited the activation of fertilized and parthenogenetic eggs. Chaetopterus sperm also contained a similar activity. These results strongly support the hypothesis that sperm PLCs are ubiquitous mediators of egg activation at fertilization.

摘要

显然，所有动物的卵子激活都需要磷脂酶C（PLC）将磷脂酰肌醇4,5-二磷酸（PIP(2)）合成肌醇1,4,5-三磷酸（InsP(3)）。根据生物体的不同，InsP(3)会引发钙振荡或单个波峰，进而启动发育过程。一种存在于公猪精子中可激活哺乳动物卵子的可溶性成分被认为是一种PLC亚型。我们使用毛翼虫的卵微粒体在体外对这一假设进行了验证。公猪精子因子通过一种依赖InsP(3)的机制引发微粒体释放Ca(2+)。PLC抑制剂U-73122而非其无活性类似物U-73343可阻断对精子因子的反应，但不影响对InsP(3)的反应。U-73122还抑制了受精卵和孤雌生殖卵的激活。毛翼虫精子也具有类似活性。这些结果有力地支持了精子PLC是受精时卵子激活的普遍介质这一假设。