(A–X) Forelimb level transverse sections of Hamburger-Hamilton stage 21–22 chicken neural tubes electroporated with Boc (A–D), BocFNIII(3) (E–H), BocΔFNIII(3) (I–L), BocFNIII(1–3) (M–P), BocΔFNIII(1) (Q–T), and BocΔFNIII(2) (U–X) stained with anti-NKX2.2 antibody (red). Green (GFP+) cells denote electroporated cells and nuclei are identified by DAPI (grayscale). Merged images are shown on the right, including quantitation of the number of embryos that display ectopic NKX2.2 expression (denoted by arrows). Scale bar, 10µm. (Y) Western Blot Analysis of COS-7 cell lysates following transfection with the specified constructs and probed with anti-HA and anti-MYC antibodies and anti-Beta-tubulin as a loading control (left panel). ImageJ quantitation of relative expression levels is expressed as a histogram (right panel).