Figure 4.

Fgf8 Reduction Rescues Maxillary Hyperplasia and Palatal Width in Compound Mutants

(A–C) Lateral views of BA1. Maxillary size is expanded in Fuz^−/− mutants in (B) compared to Fgf8^LacZ/+ in (A). Maxillary expansion is rescued in Fuz^−/−; Fgf8^LacZ/+ embryos in (C). Fgf8 expression is also rescued in compound mutants as β-gal staining reveals similar BA1 epithelial expression in compound mutants and Fgf8 heterozygotes.

(A′–C′) Maxillary size is schematized for each genotype.

(D–F) Lateral view, E12.5. Maxillary size is expanded in mutants in (E) compared to Fgf8^LacZ/+ in (D). Maxillary expansion is rescued in Fuz^−/−; Fgf8^LacZ/+ embryos in (F). Normal Fgf8 expression (β-gal/blue) is also restored in compound mutants. Brain overgrowth and eye defects are rescued in compound mutants (arrowheads).

(G–I) Trichrome staining of coronal sections of E16.5 embryos. Palatal width and bone angle are decreased in mutant embryos in (H) compared to controls in (G). Palatal width in Fuz^−/−; Fgf8^LacZ/+ in (I) appears normal compared to controls in (H). Angle of palatine bone is partially rescued when compared to controls, as shown in (I) compared to (G) and (H).

(J) Schematic of palatal anatomy.

(K) Quantification of palatal width in E16.5 Fuz^+/+; Fgf8^LacZ/+(blue), Fuz^−/−; Fgf8^+/+ (green), and Fuz^−/−; Fgf8^LacZ/+(red) embryos. Palatal width is significantly decreased in Fuz^−/−; Fgf8^+/+ compared to controls, while Fgf8 heterozygosity rescues palatal width in Fuz mutants (p < 0.0005, one-way analysis of variance). Whiskers represent maximum/minimum data values with median and quartiles represented in the box.

See also Figure S3.