UAS regulatory sequences drive expression of vn in which the endogenous EGF domain has been replaced with a chimeric EGF domain. The chimeric EGF domain consists of the A loop of the spi EGF domain and the B and C loops of the aos EGF domain.
visible, with Scer\GAL4ptc-559.1
anterior crossvein, with Scer\GAL4ptc-559.1
90% of wings lack the anterior crossvein in flies expressing argos::spi::vnS3A.Scer\UAS under the control of Scer\GAL4ptc-559.1.