Fig. 10. Overexpression of Six3, but not of Six3_F88E disrupts lens morphogenesis. Stage 10 chicken embryos were electroporated in ovo with the expression vectors indicated, together with a GFP expression vector around the head ectoderm. Twenty-four hours later, embryos were photographed for GFP fluorescence (second row), then fixed and hybridized for -crystallin mRNA (top row) and sectioned along the planes indicated in the top row (EP, third row). The shape of the lens tissue is demarcated by a white line for clarity. In the third row, the non-electroporated control side (left) of the same embryo is shown for reference, which usually bears lower hybridization signals because the side faced the bottom of the tubes during the hybridization process. A and P indicate anterior and posterior sides, respectively. (A) Control embryo electroporated with the insert-less expression vector. (B) After electroporation with Six3, -crystallin-expressing domains and -crystallin-negative domains were seen within the lens tissue (indicated by the line in the inset). Sections of the same embryo showed that the invagination of the lens placode was inhibited and confirmed the segregation of -crystallin-expressing and non-expressing domains within the placode. (C) Co-electroporation of Six3 and Grg5 caused essentially the same effect as Six3 alone. (D) Electroporation with Six3_F88E showed no effect.