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Calcium‐responsive contractility during fertilization in sea urchin eggs
Author(s) -
Stack Christianna,
Lucero Amy J.,
Shuster Charles B.
Publication year - 2006
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.20695
Subject(s) - biology , sea urchin , human fertilization , microbiology and biotechnology , myosin , contractility , cytoskeleton , calcium , actin , sperm , oocyte activation , anatomy , oocyte , botany , endocrinology , medicine , embryo , cell , biochemistry
Abstract Fertilization triggers a reorganization of oocyte cytoskeleton, and in sea urchins, there is a dramatic increase in cortical F‐actin. However, the role that myosin II plays during fertilization remains largely unexplored. Myosin II is localized to the cortical cytoskeleton both before and after fertilization and to examine myosin II contractility in living cells, Lytechinus pictus eggs were observed by time‐lapse microscopy. Upon sperm binding, a cell surface deflection traversed the egg that was followed by and dependent on the calcium wave. The calcium‐dependence of surface contractility could be reproduced in unfertilized eggs, where mobilization of intracellular calcium in unfertilized eggs under compression resulted in a marked contractile response. Lastly, inhibition of myosin II delayed absorption of the fertilization cone, suggesting that myosin II not only responds to the same signals that activate eggs but also participates in the remodeling of the cortical actomyosin cytoskeleton during the first zygotic cell cycle. Developmental Dynamics 235:1042–1052, 2006. © 2006 Wiley‐Liss, Inc.