Interaction between Foxc1 and Fgf8 during Mammalian Jaw Patterning and in the Pathogenesis of Syngnathia
Figure 4
Abnormalities of PA1 derived muscle in Foxc1−/−.
(A,B) Whole mount immunostaining for neonatal myosin II in P0 wild-type (A) and Foxc1−/− (B) heads. The PA1 masseter (ma) and temporalis (tm) muscles are smaller in the mutant than in wild-type. (C–G) Immunostained paraffin sections of E17.5 Foxc1+/+ (C, E, G) and Foxc1−/− (D, F, H) heads showing muscle actin localization (brown). Sagittal (C, D) and frontal (E, F) sections showing organized muscle formation in both wild type and mutant tongues (tg). The palate (pl) is more arched in Foxc1−/− and shows smoother rugae (r) than in Foxc1+/+. (G, H) Frontal sections in the TMJ region. The mutant temporalis muscle (tm) is shifted medially, aberrantly associates with the bifurcated condyle (cdp*), and its fibers are oriented differently than in wild type. The medial (mp) and lateral (lp) pterygoid muscles are appropriately associated with the angular (agp) and condylar processes in Foxc1−/−. The mutant masseter (ma) is reduced to a small component in Foxc1−/− (compare ma regions in F, H to E, G). (I, J) Ventral view of whole mount myosin II immunostained P0 wild type (I) and Foxc1−/− (J) heads. The second heart field derived anterior digastric muscle (ad) is robustly detected in all specimens. Scale bars: 500 µm Abbreviations: dnt, dentary; eom, extraocular muscle; f, glenoid fossa; g, genioglossus muscle; my, mylohyoid muscle; mx, maxilla; trg, trigeminal ganglion.