Fig. 7

Overexpression of rab11fip2 disrupts NC cell migration and exacerbates the Ovo1 morphant phenotype. (A-E) Rab11fip2 and mCherry mRNAs were injected into sox10:gfp transgenics, in which NC cells fluoresce green in living embryos. Dorsal views, anterior to the left at 24 hpf. (A) Controls injected with mCherry mRNA alone show bilateral sox10:gfp⁺ cells. (B) By contrast, Gfp-positive cells aggregate in the dorsal midline (arrows) following co-injection of Rab11fip2 and mCherry mRNA. (C,D) Larger aggregates (>5 cells, arrowheads) form over the midbrain in embryos co-injected with subthreshold levels of Rabfip2 mRNA and Ovo1 MO. (E) Quantitation showing proportions of wild-type (red), mild (pale blue; <5 cells per aggregate located over the hindbrain) and severe (dark blue; >5 cells per aggregate located over both the midbrain and hindbrain) NC defects. (F-M) Cell transplantation of rab11fip2 mRNA-injected cells into wild-type hosts. (F,G) Co-transplantation of sox10:gfp, Rab11fip2, mCherry mRNA-injected (green and red) and sox10:gfp uninjected control cells (green) into wild-type hosts; lateral views. Rab11fip2-overexpressing cells remain dorsally located (arrows in G). (H-M) Transplantation of control sox10:gfp⁺ (H,I) or Rab11fip2 mRNA-injected sox10:gfp⁺ cells (J-M) into uninjected hosts; lateral view (H), dorsal views (I-M). Many Rab11fip2 overexpressing NC cells remain in the dorsal midline [arrows; examples (Ex) 1-4]. Arrowheads in F-M indicate NC cells that have migrated normally. MHB, mid-hindbrain boundary; ot, otic vesicle; pa, pharyngeal arches.