title: [Polarization of eggs and embryos: some common principles].
abstract: Embryonic development depends on the establishment of polarities which define the axial characteristics of the body. In a small number of cases such as the embryo of the fly drosophila, developmental axes are established well before fertilization while in other organisms such as the nematode worm C. elegans these axes are set up only after fertilization. In most organisms the egg posesses a primary (A-V, Animal-Vegetal) axis acquired during oogenesis which participates in the establishment of the embryonic axes. Such is the case for the eggs of ascidians or the frog Xenopus whose AV axes are remodelled by sperm entry to yield the embryonic axes. Embryos of different species thus acquire an anterior end and a posterior end (Antero-Posterior, A-P axis), dorsal and ventral sides (D-V axis) and then a left and a right side.
authors.affiliation: BioMarCell, Laboratoire de biologie du développement, UMR 7009 CNRS-UPMC, Station zoologique, 06230 Villefranche-sur-Mer, France. sardet@obs-vlfr.fr
authors.forename: Christian
authors.initials: C
authors.lastname: Sardet
authors.forename: François
authors.initials: F
authors.lastname: Prodon
authors.forename: Gérard
authors.initials: G
authors.lastname: Prulière
authors.forename: Janet
authors.initials: J
authors.lastname: Chenevert
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000502:physiology; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology; D020013:Calcium Signaling; D018797:Cell Cycle Proteins / Q000502:physiology; D016764:Cell Polarity; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology; D004622:Embryo, Mammalian / Q000648:ultrastructure*; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D008954:Models, Biological; D009024:Morphogenesis; D009865:Oocytes / Q000166:cytology*; D009866:Oogenesis; D012333:RNA, Messenger / Q000502:physiology; D014561:Urochordata / Q000166:cytology / Q000196:embryology; D014982:Xenopus laevis / Q000196:embryology; D015053:Zygote / Q000648:ultrastructure
chemical_list: D018797:Cell Cycle Proteins; D012333:RNA, Messenger