Fig. 6. Repression of boundary markers by proneural genes and deltaA. Expression at 24 hours of rfng (A-H) and foxb1.2 (fox, I-L) in uninjected embryos (A,I) and embryos injected with morpholinos to block proneural gene or deltaA function, as indicated (B-H,J-L). The probe is indicated at the top right of each panel. Expansion of rfng and foxb1.2 boundary expression occurs in proneural gene knockdowns (121/145 embryos), and following deltaA knockdown (24/24 embryos). Arrowheads in I indicate boundary expression of foxb1.2, which is broader in MO embryos (brackets, J-L). Different strengths of phenotype are observed following proneural gene knockdown, asha knockdown being the strongest (B) and ngn1 the weakest (E). Ectopic expression is not seen in r4, even in a knockdown of asha, ashb plus ngn1 (G). Scale bar: 100 µm.