Sinup is localized in the centrosomes and mitotic spindles: sinup-EGFP-injected embryos were scanned with a confocal microscope with animal pole view. (A–Q) Sinup was localized in the mitotic spindle organization throughout the cell division. (R) Magnified expression domain of sinup transcripts. Asterisks indicate centrosome and arrow indicates microtubules.

Effect of misforced expression of sinup on spindle organization. (A) sinup-EGFP-injected embryo. (B) sinup144A-EGFP-injected embryo. The embryos were scanned at the sphere stage with a confocal microscope. The embryos injected with sinup144A-EGFP showed disruption in the mitotic spindle organization, orientation, and polarity of the spindle pole. Multipolar spindles were labeled with white star. (C) In vitro phosphorylation assay of Sinup144A recombinant protein. Phosphorylation of Sinup144A by Aurora A was greatly reduced in comparison with that of wild-type Sinup. (D) Purified recombinant proteins were stained with Coomassie brilliant blue on SDS-PAGE gel. 1: Marker (Fermentas #SM0671), 2: GST protein, 3: Sinup-GST, 4: Sinup144A-GST.

Knockdown of sinup expression with sinup-specific morpholino (sinup MO) alters cell movement along CE. sinup MO was injected in one- to two-cell stage embryos. Control embryos and the injected embryos were fixed at 90% epiboly (A,E), tail bud (B,F,I,K,L,M,O,P), and five-somite stages (C,D,G,H,J,N). The embryos were subjected to whole-mount in situ hybridiation with myoD (I,M), pax2.1 and myoD (J,N), dlx3 (K,O), and DAPI staining (L,I). (A–D) and (I–L) are wild type; (E–H) and (M–P) are sinup MO-injected embryos. Lateral view: A–C,E–G, L–P; dorsal view: D,H,I–K, M–O.