miR-203 expression is reduced at the time of NCC delamination. (A) Whole-mount in situ hybridization using LNA-DIG-labeled probes reveals specific expression of mature miR-203 in the neural tube that is reduced from the 5-somite stage (ss) to 9 ss. (B) Conservation analysis of mature miR-203 in vertebrates. Gga (Gallus gallus), xtr (Xenopus tropicalis), dre (Danio rerio), ola (Oryzias latipes), hsa (Homo sapiens), ptr (Pan troflodytes), mmu (Mus musculus) and pma (Petromyzon marinus). (C) RT-qPCR analyses show falling miR-203 expression from 5 to 6 ss in a reciprocal manner to the observed increases in Snai2 and Phf12 expression at the beginning of NCC delamination. (D) Transverse sections of miR-203 in situ hybridization followed by SNAIL2 (red) and PAX7 (green) immunostaining across the dorsal neural tube and delaminating/migrating NCCs.