irx2a is required upstream of etv5a for MCC genesis. (A) Dorsal view of odf3b in the pronephros by WISH at the 28 ss shows a decrease in maturing MCCs in irx2a deficient embryos, which was rescued with irx2a cRNA, etv5a cRNA, and irx2asa10776 cRNA. Scale bar is 50 μm. (B) Quantification of odf3b+ MCCs at the 28 ss. Each dot represents one pronephros. Data is presented +/− SEM and statistical significance was determined with ANOVA. WISH – whole mount in situ hybridization, ss – somite stage, MCC – multiciliated cell.