Elevation of Egfr signaling in the AS via expression of Egfr-EGFP causes down-regulation of zip expression in DME cells
dpp transcription is repressed by Egfr signaling during DC. Panels A, C, E and F are digoxigenin in situ hybridizations and panels B, D and H are FISH, with all embryos at beginning of DC. (A, B) Wild-type embryos showing horizontal dorsal and ventrolateral stripes of dpp expression. The dorsal stripe is dpp expression in the DME cells. (C, D) Egfrf2 embryo (C) and Egfrf2/Egfr2C82 embryo (D) showing ectopic dpp expression ventral to the DME cells (arrowheads). Arrow in (C) demonstrates ventrolateral stripe seen on other facet of embryo because of to diminished length amongst stripes compared to wild-type. (E) Embryo in which EgfrDN experienced been expressed in the epidermis utilizing the 69B-Gal4 driver demonstrating ectopic dpp expression (arrowhead). Arrow displays ventrolateral stripe noticeable on other side of embryo. (F) Embryo in which EgfrDN experienced been expressed utilizing the LE-Gal4 driver showing elevated dpp expression in the dorsal epidermis (arrowhead). (G, H) Rising EGFR signaling by expression of sSpi (G) or Egfr-EGFP (H) in vertical stripes utilizing the ptc-Gal4 driver leads to breaks in the dorsal and ventrolateral dpp stripes. Anti-GFP staining (H, H) reveals the expression pattern of Egfr-EGFP. Note that remnants of dpp expression (arrowheads in H) are witnessed in which Egfr-EGFP was not expressed. zip transcription is repressed by Egfr signaling during DC. zip FISH on embryos at starting of DC. (A) Wild-variety embryo showing large levels of zip transcription in DME cells and absence of zip expression in the AS. Prior to completion of germband retraction there are substantial stages of zip in the AS of wild-kind embryos (see Fig. 6A). (B) Egfrf2 embryo showing intense zip sign in DME cells and ectopic zip expression (arrowheads). (C) Mildly impacted Egfrf2 embryo displaying modest retention of zip in AS. (D, E) Embryos in which Egfr signaling experienced been impaired in the AS by expression of either EgfrDN (D) or RasN17 (E) The variation in the percentage of PH3-Ser10-good/Ki-67-good nuclei did not achieve statistical significance (p..05 Student's t-take a look at) exhibiting considerable retention of zip in AS, modest elevation of zip expression in the DME cells and ectopic zip transcripts in the head. (F) An crucial route by way of which Egfr signaling is down controlled is by clathrin-mediated endocytosis (reviewed in [100]). When imaging Egfr-EGFP in the AS for the apoptosis examine, we seen that in addition to localizing cortically in AS cells, considerably of the protein appeared to be accumulating in vesicles (Fig. 6F). Given the literature demonstrating that Ack household tyrosine kinases market down regulation of Egfr by endocytosis and subsequent degradation [292], we appeared for evidence that AS Ack was managing zip expression by way of down regulation of Egfr in this tissue.
