Figure 2

NumbL gain and loss of function studies in X. laevis embryos. (A-B) Influence of NumbL overexpression on neuronal differentiation in X. laevis embryos at the open neural plate and tailbud stage. Two cell stage embryos were coinjected animally in one blastomere with NumbL mRNA (500 pg) and β-gal mRNA (75 pg). The injected embryos were analyzed by whole mount in situ hybridization for N-tubulin. Shown is a dorsal view of stage 14 embryos, anterior up (A) and the corresponding transversal section (A') as well as a transversal section at the level of the hindbrain of a stage 26 embryo (B). (C-J) Morpholino oligonucleotide mediated knockdown of NumbL. Embryos were injected with 12.5 ng NumbL MO or a mismatched MO (mmMO) together with β-gal mRNA (75 pg) in one blastomere at the two-cell stage and analyzed by for N-tubulin expression at the open neural plate stage. To rescue the NumbL MO phenotype, 100 pg of murine NumbL or Numb mRNA as well as X. laevis NumbL mRNA was coinjected as indicated. Embryos are shown in a dorsal view, anterior up and the injected site is marked by X-Gal staining (light blue) and is always on the right. The number of embryos (n) and percentage of embryos showing the described phenotype are indicated in the lower right corner. The midline is indicated with a red arrowhead.