Fig. 3. Generation of Fgfr2 conditional knockout (Fgfr2^cko) mice. (A) Mating scheme used to produce Fgfr2^cko mice (Fgf2^flox/; Dermo1^cre/+). (B-G) In situ hybridization detection of Fgfr1 and Fgfr2 in femurs of E16.5 embryos (dark-field images). (B,C), Fgfr2 expression detected with the transmembrane domain probe, or (D,E) with the tyrosine kinase domain probe. (F,G), Fgfr1 expression. (B,D,F) Sections from normal control embryos. (C,E,G) Sections from Fgfr2^cko embryos. (H) RT-PCR analysis of Fgfr2 expression from wild-type and targeted alleles. Total RNA was prepared from E10.5 whole embryos (lanes 1 and 2) and from leg bones of E16.5 embryos (lane 3-5). Genotype of the embryo in each lane: 1, Fgfr2^+/+; 2, Fgfr2^/; 3, Fgfr2^/flox; 4, Fgfr2^+/flox and 5, Fgfr2^/flox; Dermo1^cre/+. A 820 bp fragment is generated from Fgfr2 transcripts of both wild-type and Fgfr2^flox alleles (lanes 1, 3 and 4) while a 473 bp fragment is generated from the Fgfr2 allele (lanes 2, 3 and 5). Note that both Fgfr2 alleles are transcribed in Fgfr2^/flox mice (lane 3) and full-length Fgfr2 transcripts are undetectable in skeletal tissues of Fgfr2^cko mice (lane 5). (I) The appearance of Fgfr2^cko (right) and control mice (left) at 2 weeks of age. (J) Growth curves of control (triangle) and Fgfr2^cko (circle) mice.