Fig. 4.

Adult SVZ neural stem cells are Wnt/β-catenin responsive. Representative images of brain sections from Axin2^CreERT2/+; R26R^mTmG/+ traced postnatally for various lengths of time. (A, D, H, and K) lateral ventricle; (B, E, and I) rostral migratory stream; (C, F, and J) olfactory bulb; and (G) photomontage of a sagittal section. (A) P14–P16 trace, rare subependymal GFP⁺ GFAP⁺ cells are present, as are some GFP⁺ ependymal cells (Inset). (B and C) No initial labeling is detected in the rostral migratory stream or olfactory bulb, apart from vasculature (asterisks). (D) P14–P24, 10 d after tamoxifen, increasing numbers of GFP⁺ cells can be found around the ventricle. Some GFP⁺ cells are Dlx2⁺ (closed arrowheads) and some are Dlx2⁻ (open arrowhead). (E) P14–P24, many GFP⁺ cells are detected in the rostral migratory stream, and many coexpress doublecortin (Inset). (F) P14–P24, GFP⁺ cells are found in the olfactory bulb. (G) P14–P81, many GFP⁺ cells can be found remaining at the ventricle and populating the entire rostral migratory stream. (H) P14–P379, 1 y after initial labeling, GFP⁺ cells are retained at the ventricle, (I) are present in the rostral migratory stream, and (J) fill the olfactory bulb. (K) P14–P65, rare GFP⁺ EdU⁺ subependymal cells can be found 30 d after EdU administration (Inset shows EdU). CP, choroid plexus. Asterisks in C mark vasculature; closed arrowheads point to cells of interest and double positive cells; open arrowhead in D marks a Dlx⁻ GFP⁺ cell; dashed lines in A, D, and K mark the edge of the ventricle. In all cases DAPI is shown in blue, GFP is shown in green, and all other markers in red. (Scale bar, 50 μm.)