Fig. 7. LvNumb requires a functional Notch signal. High levels of Notch signaling override the requirement for LvNumb during NSM specification and LvNumb is necessary for the expression of the earliest known Notch target. (A) (a) Pluteus larvae injected with control morpholino have normal numbers of pigment cells. (b) Injection of either ptb domain mRNA (2 pg/pl) or (f) LvN^ACT mRNA (2 pg/pl) increases pigment cell specification. (c) Embryos injected with either LvN^NEG (3 pg/pl) or (g) LvNumb morpholino display a lack of pigment cells. (d) Injection of ptb domain mRNA in embryos expressing LvN^NEG does not rescue pigment cell specification. (h) Expression of LvN^ACT (2 pg/pl) rescues pigment cell specification in 86% of the embryos injected with the LvNumb morpholino (1.8 mM). (B) (a) A mesenchyme blastula stage embryo injected with control morpholino shows gcm expression in the NSM. (b,c) Embryos injected with LvNumb2 morpholino show reduced (b) or no expression of gcm (c).