Ectopic expression of deltaD deletion and point mutant recapitulates neurogenic phenotype of DeltaD (∆A-D).

<p>(A) The prospective distribution of neurons revealed by the distribution of <i>huC</i> as revealed by <i>in situ</i> hybridization probe (purple) in control embryos injected with only <i>ß-galactosidase</i> mRNA. (B-F) <i>huC</i> in embryos co-injected with <i>ß-galactosidase</i> and <i>deltaD</i> (B), <i>deltaD-∆C</i> (C), <i>deltaD ∆B</i> (D), <i>deltaD NN/KK</i> (E) or <i>DeltaD ∆A-D</i> (F) mRNA. Distribution of ectopic mRNA injected in one cell at the two-cell stage revealed by X-Gal distribution (blue). Dorsal view, rostral to the left. Embryos are at approximately the 3 somite stage. (G) Quantification of the effect of ectopic expression of mRNA encoding various forms of DeltaD on the distribution of early neurons. Red indicates fraction with a neurogenic phenotype (increased density of neurons), Green—fraction with no obvious effect on neuron density, Blue- fraction with suppression of neurogenesis (reduced neuron density). P-values for pairwise comparison based on Fisher’s Exact test of independence. P >. 05 does not meet the criteria for the Null hypothesis that pairs contain an equivalent distribution of phenotype classes.