Fig. 1. Early expression of Tsh, Hth, Vestigial, Wg and Nubbin. (A) Expression of Vestigial (blue), Hth (red) and Tsh (green) proteins in an early second instar wing disc. The overlay is show on the left. Single channels are shown on the right. Tsh expression is low in the area indicated by the arrow. The white line indicates the position of the optical cross section shown in B. Cells expressing low levels of Tsh appear purple in the overlay on the left. The diagram on the right indicates the orientation of the optical cross sections. (C) Expression of Vestigial, Hth and Tsh in a mid second instar wing disc. Tsh is repressed in presumptive wing (arrow). The white line indicates the position of the optical cross section shown in D. (E) Expression of Tsh, Nubbin (blue) and wg-lacZ (anti-ß-gal, red) in a mid second wing disc. Tsh is repressed in presumptive wing (arrow) where wg-lacZ is expressed. Nubbin expression is not detected at this stage (white in single channel). (F) Cross-section of E.