E11.5 embryos were stained and sectioned after receiving tamoxifen administration at E7.5 (A- A‴), E8.5 (B- B‴) or E10.5 (C- C‴). (A- A‴) Administering tamoxifen at E7.5 triggers intensive reporter expression in the cranial mesenchymal cells (blank arrow in A) and meningeal cells (arrow in A), and DRG (arrow in A′) and ventral region of rostral neural tube (pink arrow in A′). Only few cells are labeled in the caudal DRG cells and no reporter expression is detected in the caudal neural tube. (B- B‴) When tamoxifen is administered at E8.5, LacZ reporter expression is induced in the DRG cells along neural tube in the rostral and more caudal level (arrows in B′ and B″), as well as in the neural tube of these regions (B′ and B″), but not at the most caudal level (B‴). (C- C‴) Administering tamoxifen at E10.5 leads to reporter expression in the cells surrounding the neural tube in the rostral region (red arrows in C′ and C″). At a more caudal level, reporter expression is detected within the neural tube (green arrow in C‴).