Fig. 1

Screen design. cdx4 heterozygous adult fish were incrossed weekly to generate embryos for the chemical screen. Chemicals from the Institute of Chemistry and Cell Biology library were transferred by robotics from 384-well plates to 48-well plates. Each plate contained negative (1% DMSO) and positive (20 μM DEAB) control wells. About 20 synchronized embryos at 50% epiboly stage were placed manually into each well of the 48-well plates. Once the embryos reached the 10-somite stage, they were fixed and whole-mount in situ hybrization was performed with both gata1 and cdx4 riboprobes. Each well was examined and scored manually. A posterior view of representative embryos is shown, with anterior to the left and posterior to the right. cdx4-mutant embryos were identified by lack of cdx4 expression. In most wells, cdx4-mutant embryos had little or no gata1 expression. The wells with increased gata1 expression in the cdx4-mutant embryos were scored as a “rescue.” DMSO, dimethyl sulfoxide; DEAB, 4-diethylamino benzaldehyde; WT, wild type. Color images available online at www.liebertonline.com/zeb.