title: How to be at the right place at the right time: the importance of spindle positioning in embryos.
abstract: Spindle positioning is an imperative cellular process that regulates a number of different developmental events throughout embryogenesis. The spindle must be properly positioned in embryos not only for the segregation of chromosomes, but also to segregate developmental determinants into different daughter blastomeres. In this review, the role of spindle positioning is explored in several different developmental model systems, which have revealed the diversity of factors that regulate spindle positioning. The C. elegans embryo, the Drosophila neuroblast, and ascidian embryos have all been utilized for the study of polarity-dependent spindle positioning, and exploration of the proteins that are required for asymmetric cell division. Work in the sea urchin embryo has examined the influence of cell shape and factors that affect secondary furrow formation. The issue of size scaling in extremely large cells, as well as the requirement for spindle positioning in developmental fate decisions in vertebrates, has been addressed by work in the Xenopus embryo. Further work in mouse oocytes has examined the roles of actin and myosin in spindle positioning. The data generated from these model organisms have made unique contributions to our knowledge of spindle positioning. Future work will address how all of these different factors work together to regulate the position of the spindle.
authors.affiliation: Department of Biology, Boston College, Chestnut Hill, Massachusetts.
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Moorhouse
authors.forename: David R
authors.initials: DR
authors.lastname: Burgess
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000166:cytology / Q000378:metabolism*; D017173:Caenorhabditis elegans; D002455:Cell Division / Q000502:physiology*; D004331:Drosophila melanogaster; D004622:Embryo, Mammalian / Q000166:cytology / Q000201:enzymology*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology*; D051379:Mice; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D008941:Spindle Apparatus / Q000502:physiology*; D014981:Xenopus