title: Centralspindlin and chromosomal passenger complex behavior during normal and Rappaport furrow specification in echinoderm embryos.
abstract: The chromosomal passenger (CPC) and Centralspindlin complexes are essential for organizing the anaphase central spindle and providing cues that position the cytokinetic furrow between daughter nuclei. However, echinoderm zygotes are also capable of forming "Rappaport furrows" between asters positioned back-to-back without intervening chromosomes. To understand how these complexes contribute to normal and Rappaport furrow formation, we studied the localization patterns of Survivin and mitotic-kinesin-like-protein1 (MKLP1), members respectively of the CPC and the Centralspindlin complex, and the effect of CPC inhibition on cleavage in mono- and binucleate echinoderm zygotes. In zygotes, Survivin initially localized to metaphase chromosomes, upon anaphase onset relocalized to the central spindle and then, together with MKLP1 spread towards the equatorial cortex in an Aurora-dependent manner. Inhibition of Aurora kinase activity resulted in disruption of central spindle organization and furrow regression, although astral microtubule elongation and furrow initiation were normal. In binucleate cells containing two parallel spindles MKLP1 and Survivin localized to the plane of the former metaphase plate, but were not observed in the secondary cleavage plane formed between unrelated spindle poles, except when chromosomes were abnormally present there. However, the secondary furrow was sensitive to Aurora inhibition, indicating that Aurora kinase may still contribute to furrow ingression without chromosomes nearby. Our results provide insights that reconcile classic micromanipulation studies with current molecular understanding of furrow specification in animal cells.
authors.affiliation: Department of Biology, New Mexico State University, Las Cruces, New Mexico, USA.
authors.forename: Haroula
authors.initials: H
authors.lastname: Argiros
authors.forename: Lauren
authors.initials: L
authors.lastname: Henson
authors.forename: Christiana
authors.initials: C
authors.lastname: Holguin
authors.forename: Victoria
authors.initials: V
authors.lastname: Foe
authors.forename: Charles Bradley
authors.initials: CB
authors.lastname: Shuster
mesh_terms: D000818:Animals; D064127:Aurora Kinases; D018797:Cell Cycle Proteins / Q000378:metabolism*; D045584:Chromosome Positioning; D002875:Chromosomes / Q000378:metabolism*; D048749:Cytokinesis; D004625:Embryo, Nonmammalian / Q000166:cytology* / Q000196:embryology / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D012617:Sea Urchins / Q000166:cytology* / Q000196:embryology*; D015398:Signal Transduction; D015053:Zygote / Q000166:cytology / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases