Fig. 7. Gsh2 can induce Isl1⁺ dI3 neurons. Framed areas in A and D are shown enlarged in C and F, respectively. (A-C) Misexpression of Gsh2 leads to an induction of ectopic Isl1⁺ dI3 neurons that is less dramatic than the induction seen following Mash1 overexpression. Arrowheads in B indicate ectopic Isl1⁺ cells. Additionally, this induction occurs in a non-cell autonomous manner (C, arrowheads). (D-F) Isl1 induction by Gsh2 is independent of Mash, as only very few ectopic Mash1⁺ cells are seen following Gsh2 overexpression. (G-I) Both Ngn1 and Ngn2 are strongly repressed (arrowheads) by Gsh2 misexpression, and this repression is apparent in both their dorsal and ventral expression domains.