title: Cell-cycle control in oocytes and during early embryonic cleavage cycles in ascidians.
abstract: The completely transparent eggs and embryos of the ascidian Phallusia mammillata are well suited for imaging-based studies of how cell cycle control mechanisms have been integrated into the processes of meiosis, fertilization, and embryonic development. Several cell cycle-related issues that pertain to reproduction and development have been addressed using the ascidian model. For example, how are sperm-triggered calcium oscillations controlled by cell cycle kinases? How is chromosome segregation during meiosis regulated? What processes does the Mos/MAPK signaling cascade control in eggs in addition to CSF-mediated cell cycle arrest? Following fertilization ascidians blastomeres display cell cycle asynchrony, oriented cell division, and unequal cleavage resulting in the formation of a distinctive gastrula composed of precisely 112 cells. Here, we shall summarize these topics and where possible show how the mechanisms identified in ascidians compare to those identified in other organisms.
authors.affiliation: Developmental Biology Unit UMR 7009, UPMC University of Paris 06 and Centre National de la Recherche (CNRS), Observatoire Océanologique, Villefranche-sur-Mer, France.
authors.forename: Alex
authors.initials: A
authors.lastname: McDougall
authors.forename: Janet
authors.initials: J
authors.lastname: Chenevert
authors.forename: Remi
authors.initials: R
authors.lastname: Dumollard
mesh_terms: D000818:Animals; D059447:Cell Cycle Checkpoints; D002970:Cleavage Stage, Ovum / Q000166:cytology* / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000166:cytology* / Q000378:metabolism; D009865:Oocytes / Q000166:cytology*; D008941:Spindle Apparatus / Q000378:metabolism; D014561:Urochordata / Q000166:cytology* / Q000196:embryology*