Figure 3

X. laevis NumbL inhibits Notch signaling in reporter assays, but knockdown of NumbL does not influence the expression of Notch target genes in the open neural plate. (A) The influence of NumbL overexpression on a Notch responsive reporter. X. laevis embryos were injected with the Notch-ICD (NICD), Noggin and NumbL mRNA as indicated, together with a Hes1-luciferase reporter. Embryos were cultivated until open neural plate stage and luciferase activity was measured and normalzed to renilla luciferase. Shown is a summary of four independent luciferase experiments. Two batches of embryos containing at least ten embryos per injection mix were collected for each experiment. The error bars represent the standard deviation. (B-E) NumbL MO (12.5 ng) does not lead to an increase in Notch target gene expression at open neural plate stages. (F-I) The NumbL MO induced loss of neuronal differentiation is not rescued by inhibition of Notch signaling. Delta^Stu or Su(H)^DBM mRNA was injected alone or in combination with 12.5 ng NumbL MO into one blastomere at the two-cell stage and N-tubulin expression analyzed by whole mount in situ hybridization at stage 14. Whole mount in situ probes are indicated in the lower left corner. Embryos are shown in a dorsal view, anterior up. The injected side is marked by X-Gal staining and is always on the right. The midline is indicated with a red arrowhead.