title: Coupling of rotational cortical flow, asymmetric midbody positioning, and spindle rotation mediates dorsoventral axis formation in C. elegans.
abstract: Cortical flows mediate anteroposterior polarization in Caenorhabditis elegans by generating two mutually exclusive membrane domains. However, factors downstream of anteroposterior polarity that establish the dorsoventral axis remain elusive. Here, we show that rotational cortical flow orthogonal to the anteroposterior axis during the division of the AB blastomere in the two-cell embryo positions the cytokinetic midbody remnant of the previous division asymmetrically at the future ventral side of the embryo. In the neighboring P1 blastomere, astral microtubules contact a transient PAR-2-dependent actin coat that forms asymmetrically onto the midbody remnant-P1 interface. Ablation of the midbody remnant or perturbation of rotational cortical flow reveals that microtubule-midbody remnant contacts are crucial for P1 spindle rotation and dorsoventral axis formation. Thus, our findings suggest a mechanism for dorsoventral patterning that relies on coupling of anteroposterior polarity, rotational cortical flow, midbody remnant positioning, and spindle orientation.
authors: Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt (Main), Germany.
authors: Deepika
authors: D
authors: Singh
authors: Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt (Main), Germany. Electronic address: pohl@em.uni-frankfurt.de.
authors: Christian
authors: C
authors: Pohl
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000502:physiology*; D016764:Cell Polarity; D048429:Cell Size; D048749:Cytokinesis / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000166:cytology*; D008870:Microtubules / Q000378:metabolism; D008941:Spindle Apparatus / Q000502:physiology*
chemical_list: D000199:Actins; D029742:Caenorhabditis elegans Proteins; C087977:par-2 protein, C elegans