Practice question

Overexpression of Pax6 in competent head surface ectoderm results in ectopic lens formation at sites outside normal eye region. Transgenic misexpression or electroporation of Pax6 into head ectoderm induces ectopic Sox2, Six3, L-Maf, and crystallin expression forming additional lens vesicles that may recruit surrounding mesenchyme and attempt optic cup-like differentiation. No suppression of FGF signaling or inhibition of Sox2 occurs; instead synergistic activation. Surface ectoderm normally expresses low Pax6, elevating levels confers increased competence recapitulating master regulatory property previously described for eyeless gene in Drosophila eye induction and vertebrates.