The apterous expression pattern in the left wing disc over time in flies expressing UAS CD8-GFP under the control of apGAL4.

<p>The wing disc is indicated by the lighter area. <b>A:</b> second instar wing disc, with first ap expression. <b>B:</b> same wing disc the next day (about 16(1) h after the first image (AFI)). <b>C:</b> 24(1) h AFI. <b>D:</b> 40(1) h AFI. The larva is in the third instar. In this and the following image it can be seen that the D/V boundary is not yet smooth but rather appears to be determined by non-oriented cell divisions<b>. E:</b> 48(1) h AFI. <b>F:</b> 64(1) h AFI. The D/V boundary is now smooth and well-defined. <b>G:</b> 72(1) h AFI. <b>H:</b> 88(1) h AFI. <b>I:</b> 96(1) h AFI. <b>J:</b> 112(1) h AFI. The scale bar is 50 µm in all images.