title: The dynamics of plus end polarization and microtubule assembly during Xenopus cortical rotation.
abstract: The self-organization of dorsally-directed microtubules during cortical rotation in the Xenopus egg is essential for dorsal axis formation. The mechanisms controlling this process have been problematic to analyze, owing to difficulties in visualizing microtubules in living egg. Also, the order of events occurring at the onset of cortical rotation have not been satisfactorily visualized in vivo and have been inferred from staged fixed samples. To address these issues, we have characterized the dynamics of total microtubule and plus end behavior continuously throughout cortical rotation, as well as in oocytes and unfertilized eggs. Here, we show that the nascent microtubule network forms in the cortex but associates with the deep cytoplasm at the start of rotation. Importantly, plus ends remain cortical and become increasingly more numerous and active prior to rotation, with dorsal polarization occurring rapidly after the onset of rotation. Additionally, we show that vegetally localized Trim36 is required to attenuate dynamic plus end growth, suggesting that vegetal factors are needed to locally coordinate growth in the cortex.
authors.affiliation: The University of Iowa, Department of Biology, 257 BB, Iowa City, IA 52242-1324, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Olson
authors.affiliation: The University of Iowa, Department of Biology, 257 BB, Iowa City, IA 52242-1324, USA.
authors.forename: Denise
authors.initials: D
authors.lastname: Oh
authors.affiliation: The University of Iowa, Department of Biology, 257 BB, Iowa City, IA 52242-1324, USA. Electronic address: douglas-houston@uiowa.edu.
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Houston
mesh_terms: D000818:Animals; D001368:Axis, Cervical Vertebra / Q000196:embryology; D019521:Body Patterning; D002352:Carrier Proteins / Q000378:metabolism; D004625:Embryo, Nonmammalian; D049452:Green Fluorescent Proteins / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology / Q000254:growth & development*; D061848:Optical Imaging; D010063:Ovum / Q000166:cytology / Q000254:growth & development*; D012399:Rotation; D014981:Xenopus; D029867:Xenopus Proteins / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases; D000070584:Tripartite Motif Proteins
chemical_list: D002352:Carrier Proteins; D049452:Green Fluorescent Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; D029867:Xenopus Proteins; C534481:Trim36 protein, Xenopus; D044767:Ubiquitin-Protein Ligases; D000070584:Tripartite Motif Proteins
keywords: Axis formation; Cortical rotation; Egg; Microtubules; Oocyte; Plus ends; Polarity; Trim36; Xenopus