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Figure 5 | BMC Developmental Biology

Figure 5

From: Cropped, Drosophila transcription factor AP-4, controls tracheal terminal branching and cell growth

Figure 5

Expression of dominant-negative Cropped leads to missing cells and disruption of organ development. (A) Overexpressing DN-crp by using btl-Gal4 in the tracheal system led to disruption of the formation of terminal and fusion cells (i and ii); the arrow heads point to the ends of DBs. (iii and iv) Larvae show a collapse in dorsal trunk. (i and iii) are fluorescence images of GFP-labeled tracheal cells and (ii and iv) are the same field under DIC optics. (B) Expression of DN-crp in the salivary glands driven by A9-Gal4 shrank the organs (ii) compared with control (i) under the same magnification. (C) Staining assay on the cells expressing crp and DN-crp in the salivary glands for apoptosis with changes in permeability by PI (i-iv) and breakage of DNA strands by the TUNEL assay (v-viii). DIC photomicrographs (i, iii, v, vii) and fluorescence microscopy (ii, iv, vi, viii) were taken under the same magnification. (D) Scanning electron micrographs of the ommatidia expressing DN-crp or WT crp driven by GMR-Gal4. (i-iv) The anterior of the fly is pointing to the left and the posterior to the right. DN-crp inhibited the formation of ommatidia and bristles in the posterior half of the eyes and WT crp caused overgrowth of groups of ommatidia. The white arrowheads indicate groups of protruding ommatidia in (ii and iii) and the yellow arrowheads points to the posterior end of the eye without any ommatidia. Scanning micrographs at higher magnification of the ommatidia from WT (v), WT crp- (vi), and DN-crp-expressing fly (vii) are shown. (vii) Electron micrograph taken from the dorsal side of the eye of DN-crp expressing fly and the anterior is to the left. Scale bars are 100 μm (A, B, and C), 200 μm (Di-iv), 20 μm (Dv,vi), and 50 μm (Dvii).

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