Mouse oocytes fertilised by ICSI during in vitro maturation retain the ability to be activated after refertilisation in metaphase II and can generate Ca2+ oscillations

摘要

BackgroundAt fertilisation, mammalian oocytes are activated by oscillations of intracellular Ca²⁺ ([Ca²⁺]i). Phospholipase Cζ, which is introduced by fertilising spermatozoon, triggers [Ca²⁺]i oscillations through the generation of inositol 1,4,5-triphosphate (IP3), which causes Ca²⁺ release by binding to IP3 receptors located on the endoplasmic reticulum (ER) of the oocyte. Ability to respond to this activating stimulus develops during meiotic maturation of the oocyte. Here we examine how the development of this ability is perturbed when a single spermatozoon is introduced into the oocyte prematurely, i.e. during oocyte maturation.