Loss of Sip1 affects neural crest gene expression. (A) Whole-mount in situ hybridization with a probe for FoxD3 in embryos electroporated with Sip1 morpholino (MO) on the right side and analyzed at HH9. A section of an embryo in A showing FoxD3 expression (a′) after Sip1MO injection marked by FITC (a′′). FoxD3 is up-regulated on the Sip1MO side (n = 19/33). (B and C) Whole-mount in situ hybridization with a probe for Sox10 in embryos electroporated with (B) ContMO (left side) and Sip1MO (right side) showing loss of Sox10 expression (n = 25/29), or (C) Sip1MO (left side) and Sip1MO + Zeb2 DNA showing rescue of that loss (C; n = 10/21). (D) Immunohistochemistry for Pax7 in embryos with ContMO on the left side and Sip1 MO on the right side (green is FITC from ContMO on left and Sip1MO on right). (d′) A section from embryo, in D as indicated by dashed line, showing maintenance of Pax7 expression in premigratory cells but fewer migratory cells (n = 9/10). Right panel is overlay with ContMO and Sip1MO FITC. Bars: (A–d′) 200 µm. The data shown here are from a single representative experiment out of at least three repeats.