Figure 1.

Pipette feeding of tamoxifen to pregnant female mice activates various embryonic CreERT2 drivers relevant for developmental biology research. (a–d) CreERT‐negative female mice were lightly scruffed and fed a single dose of 75 μl peanut oil containing 100 mg/ml tamoxifen free base. Recombination of Rosa26 ^YFP (b) or Rosa26 ^mTmG (a, c, d) reporters, producing green fluorescence. (a) Stereoscope image of Actin ^CreERT2‐positive (arrows) and negative (circles) embryos collected at E7.5, 24 h after tamoxifen administration. (b) Stereoscope image showing extensive Sox2 ^CreERT2 recombination in an embryo collected at E8.5, 24 h after tamoxifen. (c) Stereoscope image showing Nkx1.2 ^CreERT2 recombination in an embryo collected at E10, 36 h after tamoxifen. (d) Confocal image of a dorsal view of the caudal end of a T ^CreERT2–expressing embryo showing lineage tracing of both neuroepithelial (NE) and mesodermal (M) populations. Long arrows indicate the tail end in the confocal image; scale bar = 100 μm