title: Rhythmic actomyosin-driven contractions induced by sperm entry predict mammalian embryo viability.
abstract: Fertilization-induced cytoplasmic flows are a conserved feature of eggs in many species. However, until now the importance of cytoplasmic flows for the development of mammalian embryos has been unknown. Here, by combining a rapid imaging of the freshly fertilized mouse egg with advanced image analysis based on particle image velocimetry, we show that fertilization induces rhythmical cytoplasmic movements that coincide with pulsations of the protrusion forming above the sperm head. We find that these movements are caused by contractions of the actomyosin cytoskeleton triggered by Ca(2+) oscillations induced by fertilization. Most importantly, the relationship between the movements and the events of egg activation makes it possible to use the movements alone to predict developmental potential of the zygote. In conclusion, this method offers, thus far, the earliest and fastest, non-invasive way to predict the viability of eggs fertilized in vitro and therefore can potentially improve greatly the prospects for IVF treatment.
authors.affiliation: Wellcome Trust/Cancer UK Gurdon Research Institute, University of Cambridge, Cambridge CB2 1QN, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Ajduk
authors.forename: Tagbo
authors.initials: T
authors.lastname: Ilozue
authors.forename: Shane
authors.initials: S
authors.lastname: Windsor
authors.forename: Yuansong
authors.initials: Y
authors.lastname: Yu
authors.forename: K Bianka
authors.initials: KB
authors.lastname: Seres
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bomphrey
authors.forename: Brian D
authors.initials: BD
authors.lastname: Tom
authors.forename: Karl
authors.initials: K
authors.lastname: Swann
authors.forename: Adrian
authors.initials: A
authors.lastname: Thomas
authors.forename: Chris
authors.initials: C
authors.lastname: Graham
authors.forename: Magdalena
authors.initials: M
authors.lastname: Zernicka-Goetz
mesh_terms: D000205:Actomyosin / Q000378:metabolism*; D000818:Animals; D002470:Cell Survival; D003595:Cytoplasmic Streaming; D004622:Embryo, Mammalian / Q000378:metabolism; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D010063:Ovum / Q000378:metabolism; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000378:metabolism*; D015053:Zygote / Q000378:metabolism
chemical_list: D000205:Actomyosin