Fig. 8. MO-induced depletion of GATA-6 in zebrafish embryos inhibits maturation of cardiac precursors. (A) The zfMDL MO binds to 25 nucleotides of GATA-6 sequence around the ATG. (B) Western blot showing that the translation of zfGATA6 (MDL) in Xenopus animal caps is inhibited by zfMDL MO. (C) Downregulation of zfGATA6 results in reduced numbers of cells expressing cardiac genes and cardia bifida at 26 h.p.f. (dorsal views). See Supplementary table 1 for numbers. (D) zfSCL MO has no effect on Vmhc expression (dorsal views). Reduced and patchy GATA-1 expression (dorsal view) in embryos injected with zfSCL MO indicates that the MO was functioning. (E) Nkx2.5 expression initiates normally in zfMDL MO-injected embryos but, by 10 somites, expression is slightly reduced in 10/13 embryos. At 18 somites, 13/19 injected embryos showed a stronger reduction. (F and G) GATA-4 and -5 expression is unaffected by zfMDL MO injection.