Mnx proteins prevent MiPs from acquiring V2a-like molecular characteristics. (A-D) Single spinal hemisegments of control and mnx MO-injected embryos. MiPs (closed arrowheads) and CaPs (open arrowheads) are indicated in merged panels (right column). (A) In control embryos, MiPs and CaPs express chat but never vglut (0/20 vglut+ MiPs or CaPs in five embryos). (B) In mnx MO-injected embryos, MiPs co-express both chat and vglut (22/41 vglut+ MiPs in eight embryos), while CaPs express chat but not vglut (0/41 vglut+ CaPs in eight embryos. (C) In control embryos, MiPs express islet1 but not vsx2 (0/50 vsx2+ MiPs in 10 embryos), while CaPs express neither islet1 nor vsx2 (0/50 vsx2+ CaPs in 10 embryos). (D) In mnx MO-injected embryos, MiP express vsx2 but not islet1 (26/60 vsx2+ MiPs in 13 embryos) while CaPs express neither vsx2 nor islet1 (0/60 vsx2+ CaPs in 13 embryos). Scale bar: 10 μm.