Molecular mechanisms for defining tectum territory in chick embryogenesis

Optic tectum derives from the midbrain alar plate in early chick developmen t. To know the molecular mechanism defining tectum territory along the ante roposterior (AP) and dorsoventral (DV) axis in neural development, we have carried out the gain-of-function experiments using a newly developed gene t ransfer system, in ovo electroporation. Misexpression of Otx2/Gbx2 and Shh changed the expression of tectum-related genes, resulting in the fate chang e of the tectum structure along the AP axis and the DV axis, respectively. We conclude that these genes are involved in the establishment of tectum te rritory in embryogenesis.