Figure 1

Generation and validation of Fgf8 ^CreER and Fgf17 ^CreER mouse lines. (A) In the Fgf8 ^CreER allele, the first 20 nucleotides of exon 1 coding sequence were replaced with CreER-SV40 pA-loxP-neo-loxP cassette, and the long arm of homology began 12 nucleotides upstream of the exon 1/intron 1 junction. In the Fgf17 ^CreER allele, all exon 1 coding sequences were replaced with CreER-SV40 pA. All Fgf17 intronic sequences were included in the targeted allele, but intron 2 was interrupted by insertion of the loxP-neo-loxP cassette and, further downstream, by a small insertion of MCS restriction enzyme sites. Symbols: small arrows, genotyping oligos; red rectangles, Southern blot probes. (B) Fgf8 ^CreER/+ and (C) Fgf17 ^CreER/+ Southern blots demonstrating correct targeting. (D) Fgf8 and Fgf17 whole mount ISHs (frontal view) showing mRNA expression in the rostral telencephalon of 12-s embryos. (E,F) E10.5 ISHs (horizontal sections) comparing Fgf8 versus Cre mRNA in an Fgf8 ^CreER/+ brain (E), and Fgf17 versus Cre mRNA expression in an Fgf17 ^CreER/+ brain (F). Sequential panels in (E) and (F) show successively more caudal planes of section. Abbreviations: B, BamHI; E, EcoRI; N, NdeI; S, SacI; X, XhoI; Di, diencephalon; MH, midbrain/hindbrain patterning center; Hy, hypothalamus. See also Additional file 1: Figure S1.