(A) Localization of the basal-specific optogenetic anchor CIBN-PatJ::GFP-pm during ventral furrow formation. Embryos expressing CIBN-PatJ::GFP-pm were imaged using two-photon excitation during ventral furrow formation. Transverse cross section (z-projection) at a stage when cells were already apically constricted and elongated, and the ventral tissue already internalized. 