Fig. 4. duf-lacZ expression in developing DLMs. (A) The position of the larval templates and the six DLM fibres with respect to the fly notum. (B) The three larval templates at 12 hours APF; (C) the six DLM fibres at 26 hours APF, as revealed by histochemical staining in Mhc-lacZ pupae. (D-G) duf-lacZ expression followed by assaying for ß-galactosidase activity (D) and anti-ß-galactosidase labeling (E-G). (D) A 6.5-hour APF duf-lacZ pupal preparation showing ß-galactosidase histochemical activity in the three larval templates. The three templates have been labeled as LOM I, II and III. Each template has 8-13 duf-lacZ-expressing nuclei aligned along their length. Some nuclei in LOM I and LOM II are out of focus. (E-G) duf-lacZ expression at 12 hours APF (E), 14 hours APF (F) and 24 hours APF (G), when the DLMs are in the six fibre stage. (H-J) Confocal images of a 12-hour APF duf-lacZ pupa stained with anti-ß-galactosidase (green) and anti-Ewg (red) antibodies. (H) The three larval templates expressing duf-lacZ. (I) Ewg expression in larval nuclei, and in the nuclei of incoming adult myoblasts. White arrowhead points to a larval nucleus expressing Ewg in the template fibre; arrows indicate the adult nuclei. Note the difference in size between the nuclei of the two different origins. (J) Merged image showing the co-localization of ß-galactosidase (green) with Ewg (red), expressed in the larval nuclei. Anterior is to the top; dorsal midline to the right. Scale bar 20 µm for D-J.