Fig. 10

A model for Pitx controlling the asymmetry of pharyngeal organs. At early neurula stage (before N4 stage), Pitx expression (gradient purple region) is in a gradient manner along the dorsal-ventral axis. During the process, Pitx promotes the development of organs on the left through directly activating expression of Lhx3, Prop1, or/and Pit (blue region). Meanwhile, Pitx is a dominant factor together with an unknown factor X, and both factors are located downstream of Nodal signaling pathway, inhibiting the formation of right-side organs by directly repressing expression of Hex, Nkx2.1, or/and FoxE4 (gradient green region) on the left side. D, dorsal; V, ventral; L, left side; R, right side