Sprouty genes are essential for the normal development of epibranchial ganglia in the mouse embryo.
Bottom Line: Fibroblast growth factor (FGF) signalling has important roles in the development of the embryonic pharyngeal (branchial) arches, but its effects on innervation of the arches and associated structures have not been studied extensively.However, epithelial-specific gene deletion only results in defects in the facial nerve and not the glossopharyngeal and vagus nerves, suggesting that the facial nerve is most sensitive to perturbations in RTK signalling.Reducing the Fgf8 gene dosage only partially rescued defects in the glossopharyngeal nerve and was not sufficient to rescue facial nerve defects, suggesting that FGF8 is functionally redundant with other RTK ligands during facial nerve development.
Affiliation: Department of Craniofacial Development, King's College London, Floor 27, Guy's Tower, London, SE1 9RT, UK.Show MeSH
Related in: MedlinePlus
Mentions: In agreement with this hypothesis, Spry1−/−;Spry2−/− embryos (n = 36) displayed severe abnormalities in all the branchial nerves at E10.5 (Fig. 2E,E′, Table 1). An abnormally developing facial nerve (VII) was the most prevalent defect observed in Spry1−/−;Spry2−/− embryos (n = 35/36). In control embryos, the VIIth nerve penetrated the proximal second arch and turned anteriorly once it reached the distal arch (Fig. 2A and Suppl. Fig. 3). Nerve projections from the facial ganglion into the second arch appeared stunted and failed to turn in an anterior direction (red arrow in Fig. 2E,E′, n = 34/36, two-tailed Fisher's exact text, p < 0.0001). In some cases, the VIIth nerve also exhibited severe defasciculation (Fig. 2E′, Suppl. Fig. 3).
Affiliation: Department of Craniofacial Development, King's College London, Floor 27, Guy's Tower, London, SE1 9RT, UK.