Transcription regulator acting downstream of both FOXA2 and T during notochord development. Required for node morphogenesis. Is essential for cilia formation in the posterior notochord (PNC) and for left-right patterning; acts upstream of FOXJ1 and RFX3 in this process and is required for the expression of various components important for axonemal assembly and function. Plays a role in regulating axial versus paraxial cell fate.