Apical localization of ASIP/PAR-3:EGFP in zebrafish neuroepithelial cells involves the oligomerization domain CR1, the PDZ domains, and the C-terminal portion of the protein.
Neurulation in zebrafish (Danio rerio) embryos is characterized by oriented cell divisions and the progressive establishment of cellular polarity. Mitoses in the neural plate and neural tube are planar, but in the neural keel/rod stage, the mitotic spindle rotates by 90 degrees, causing cell divisions to occur perpendicular to the plane of the neuroepithelium. The mechanisms and molecules that establish cellular polarity and cause the stereotypic orientation of the mitotic spindle during neurulation are largely unknown. In Caenorhabditis elegans and Drosophila, the PAR/aPKC complex has been shown to be involved in both establishment of cellular polarity and spindle orientation. Here, we show that the conserved N-terminal oligomerization domain (CR1) and the PDZ domains of ASIP/PAR-3:EGFP are involved in its localization to the apical membrane in zebrafish neuroepithelial cells. We further show that the C-terminal part of ASIP/PAR-3 contributes to proper localization and that the apical localization signals in ASIP/PAR-3 prevent the basolateral localization of a Numb:PAR-3 fusion protein. The parallel orientation of the mitotic spindle in the neural tube, however, is only weakly impaired upon overexpression of various ASIP/PAR-3:EGFP constructs.
Institut für Entwicklungsbiologie, Universität zu Köln, 50923 Köln, Germany.
Jakob W
JW
von Trotha
José A
JA
Campos-Ortega
Alexander M
AM
Reugels
D000595:Amino Acid Sequence; D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016764:Cell Polarity; D004625:Embryo, Nonmammalian; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D008845:Microinjections; D018613:Microscopy, Confocal; D018715:Microscopy, Video; D008969:Molecular Sequence Data; D046569:Neuroepithelial Cells / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D029961:Zebrafish Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C097238:PAR-3 protein, C elegans; D017346:Protein Serine-Threonine Kinases