Basson:Jenny Gardiner

Thymus/parathyroid organogenesis
The thymus and parathyroid glands are glands of the immune and calcium-regulating systems respectively. The glands develop from a common primordium in the 3rd pharyngeal pouch endoderm in the mouse embryo. Previous research has implicated Fgf signalling in pouch formation at around E9.5 and in proliferation of the thymic primordium from E12. Very little is known about the role of Fgf signalling at intermediate stages; E10.5, when subdivision of the 3rd pouch into prospective Foxn1-positive thymus and Gcm2-positive parathyroid domains becomes apparent, and E11.75, when the third pouch separates from the pharynx. Sprouty (Spry) genes encode intracellular feedback antagonists of Fgf signalling. Spry1 and Spry2 are expressed in all tissues of the 3rd pharyngeal arch during pouch patterning. Simultaneous deletion of both Spry1 and Spry2 results in parathyroid hypoplasia, and thymic ectopia. My project aims to use deletion of the Spry genes in mice to modulate Fgf signalling, and so to determine the role of Fgf signalling between E10.5 and E11.75.