Expression of Tc-col and Tc-en in wildtype and Tc-kni RNAi embryos. Abnormalities in Tc-en expression in Tc-kni RNAi embryos are similar to those seen in Figure 2 and described in the text. The appearance of the Tc-col domain in early germband embryos may be slightly delayed following Tc-kni RNAi (compare panels B, C to panel A). Apart from minor irregularities, the Tc-col expression domain is not strongly altered in Tc-kni RNAi embryos (compare wildtype to Tc-kni RNAi embryos in panels D-O). The co-expression of Tc-col and Tc-en in a medial region of the head in mid-to-late germband embryos (black asterisk in panels J-L, N-O, obscured by antennae in M) confirms the identity and presence of intercalary Tc-en expression in a Tc-kni RNAi background. White arrowheads: Tc-en antennal stripe. Black arrows: Tc-en mandibular stripe. Black arrowheads: Tc-en maxillary stripe. Red arrows: Residual Tc-en expression associated with structures at the base of the antennae. Ventral views, and anterior towards the top, in all panels.