title: Ooplasmic segregation in the zebrafish zygote and early embryo: pattern of ooplasmic movements and transport pathways.
abstract: Patterns of cytoplasmic movements and organization of transport pathways were examined in live or fixed zygotes and early zebrafish embryos using a variety of techniques. The zygote blastodisc grows by accumulation of ooplasm, transported to the animal pole from distinct sectors of ecto- and endoplasm at different speeds and developmental periods, using specific pathways or streamers. Slow transport (5 microm/min) occurs during the first interphase along short streamers, whereas fast transport (9.6-40 microm/min) takes place during the first cleavage division along axial and meridional streamers. Interconnections between streamers allow cargoes to change their speed and final destination. A similar sequence of events occurs during the following divisions. A complex network of microtubules and actin filaments in the endo- and ectoplasm appears to be involved in the transport of inclusions and mRNAs. Actin-dependent intermittent pulsations provoked high-speed back-and-forth movements of cytoplasm that may contribute to redistribution of organelles and maternal determinants.
authors.affiliation: Laboratory of Developmental Cell Biology, Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Fuentes
authors.forename: Juan
authors.initials: J
authors.lastname: Fernández
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D019521:Body Patterning; D002465:Cell Movement; D003593:Cytoplasm / Q000378:metabolism; D004625:Embryo, Nonmammalian; D005260:Female; D002479:Inclusion Bodies / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D009865:Oocytes / Q000166:cytology*; D015388:Organelles / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015027:Zebrafish; D015053:Zygote / Q000166:cytology*
chemical_list: D012333:RNA, Messenger