Fig. 5. StripeA and StripeB exhibit differential transcriptional output. (A-F) Stage 15 wild-type embryos (WT; A,B) or embryos overexpressing StripeB (C,D) or StripeA (E,F) driven by the pan-ectodermal driver 69B-gal4 were double-labeled for Slit (red, A,C,E) and for Stripe (green) (merged view is shown in B,D,F). Arrows in A and B show Slit expression pattern close to the Stripe-expressing cells. A significant elevation of Slit is detected in both overexpressing embryos. (G-L) In situ analysis of wild-type embryos (G,J) or embryos overexpressing StripeB (H,K) or StripeA (I,L) using en-gal4 driver with probes specific to how(L) (G-I) or how(S) (J-L) mRNAs. While both StripeA and StripeB induce the expression of how(L) mRNA, only StripeA induces the expression of how(S) mRNA. (Brackets indicate the segmental border expression domain). (M) The effect of StripeA or StripeB overexpression driven by ptc-gal4 driver on the endogenous levels of stripeA or stripeB mRNA levels in 13-16-hour-old embryos, as measured by RT-PCR performed on RNA samples using primers specific for the endogenous stripeA or stripeB mRNA.