Fig. 4. Downregulation of Fgf3 and Fgf19 expression downregulates both early and late otic genes. (A) The introduction of shFgf3 downregulates endogenous expression of Fgf3 in the mesoderm of 1-4ss chick embryos. Sections show a reduction of Fgf3 expression in regions that express the mCherry tracer. (B) Introduction of shFgf19 reduces endogenous Fgf19 expression in the mesoderm of 1-4ss chick embryos. Sections show a reduction of Fgf19 expression in regions that express the mCherry tracer. (C) Control embryos electroporated with control shScrambled show no change in Pax2 expression (n=19/21). (D)shFgf3 electroporation results in a slight reduction of Pax2 OEPD expression (n=17/38). (E)shFgf19 causes a slight reduction in Pax2 expression (n=15/30). (F) Electroporation of both shFgf3 and shFgf19 causes a strong reduction of the normal Pax2 OEPD expression domain (n=13/21). (G) Control embryos electroporated with shScrambled show no change in Soho1 expression (only one out of 10 showed aberrant expression). (H)shFgf3 electroporation results in a slight reduction of Soho1 expression (n=8/14). (I)shFgf19 causes a slight reduction in Soho1 expression (n=9/15). (J) Electroporation of both shFgf3 and shFgf19 causes a strong reduction of normal Soho1 otic expression (n=12/19). In all cases, the electroporated side is on the right.