Figure 1.

Notch1 iKO mice have fewer YFP+ cells in the SGZ. a, Nestin-CreER^T2 and R26R-YFP mice were crossed with floxed Notch1 mice to generate Notch1 iKO mice. A large portion of the rat nestin gene drives expression of a fusion protein of Cre recombinase and the modified estrogen receptor (CreER^T2). Administration of tamoxifen (TAM) results in removal of the promoter and first exon of notch1, and the “stop” signal of R26R-YFP. This leads to elimination of Notch1 and to expression of YFP in nestin-expressing cells and their progeny. b, PCR of neurospheres isolated 40d post-TAM confirmed that the notch1 locus was recombined after TAM in Notch1 iKO mice but not WT littermates. Primers (indicated by arrows in a) were designed against regions outside the floxed portion of notch1. c, YFP+ SGZ cells in WT and Notch1 iKO mice. d, YFP+ SGZ cell number. **p < 0.01, ***p < 0.001 vs WT, Bonferroni post hoc; n = 5–11/group. Scale bar: (c), 50 μm.