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Calcium oscillations and mammalian egg activation
Author(s) -
Malcuit Christopher,
Kurokawa Manabu,
Fissore Rafael A.
Publication year - 2006
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.20471
Subject(s) - oocyte activation , sperm , inositol , endoplasmic reticulum , calcium signaling , microbiology and biotechnology , calcium , phospholipase c , biology , human fertilization , receptor , inositol trisphosphate receptor , calcium in biology , intracellular , phospholipase , embryo , signal transduction , chemistry , biochemistry , embryogenesis , anatomy , genetics , organic chemistry , enzyme
Fertilization in all species studied to date induces an increase in the intracellular concentration of free calcium ions ([Ca 2+ ] i ) within the egg. In mammals, this [Ca 2+ ] i signal is delivered in the form of long‐lasting [Ca 2+ ] i oscillations that begin shortly after fusion of the gametes and persist beyond the time of completion of meiosis. While not fully elucidated, recent evidence supports the notion that the sperm delivers into the ooplasm a trigger of oscillations, the so‐called sperm factor (SF). The recent discovery that mammalian sperm harbor a specific phospholipase C (PLC), PLCζ has consolidated this view. The fertilizing sperm, and presumably PLCζ promote Ca 2+ release in eggs via the production of inositol 1,4,5‐trisphosphate (IP 3 ), which binds and gates its receptor, the type‐1 IP 3 receptor, located on the endoplasmic reticulum, the Ca 2+ store of the cell. Repetitive Ca 2+ release in this manner results in a positive cumulative effect on downstream signaling molecules that are responsible for the completion of all the events comprising egg activation. This review will discuss recent advances in our understanding of how [Ca 2+ ] i oscillations are initiated and regulated in mammals, highlight areas of discrepancies, and emphasize the need to better characterize the downstream molecular cascades that are dependent on [Ca 2+ ] i oscillations and that may impact embryo development. © 2005 Wiley‐Liss, Inc.