Fig. 5. shot is a Notch target gene and required for Notch signalling. (A,B) Anti-Shot (red)/anti-Dve (green) immunostaining of stage 17 wild-type (A) and Notch (B) mutant embryos. Upregulation of Shot expression in the posterior boundary cells (pc) does not occur in Notch mutants (arrow). (C) Shot mRNA expression in a wild-type embryo of stage 17 and in an embryo in which the Notch pathway has been ectopically activated (D). Note the ectopic activation of shot transcription as compared with wild type. (E,F) Anti-Notch^ECD immunostaining of the proventriculus primordium of stage 14 wild-type (E) and shot mutant embryos (F). Arrows in E and F indicate the keyhole. Notch receptor expression is strongly reduced in the ectodermal keyhole (ky) domain in shot mutants. (G,H) Anti-ß-Gal(red)/anti-Fas3 (green) double staining of late stage 14 Gbe-Su(H)m8-lacZ embryos in a wild-type (G) and a shot mutant embryo (H); note the loss of reporter gene expression in pc. (I,J) Anti-ßGal(red)/anti-Dve (green) double staining of stage 17 Gbe-Su(H)m8-lacZ embryos in wild-type (I) and shot mutant background (J). The activity of the Notch signalling pathway is strongly reduced in the posterior boundary cells (pc).