Figure 3.

Over-expression of skp2 blocks primary neurogenesis and reduces cell proliferation. (a-e) Embryos were injected with 1 ng wild-type (Wt) skp2 (a,d), 1 ng FBox skp2 (b,e), or 1 ng Wt MAFbx (c) mRNA, along with ßgal mRNA as a lineage tracer, in one blastomere at the two cell stage. Embryos were analyzed for expression of nßt mRNA (a-c) at stage 15. Dorsal views with injected side to the right. (d,e) Whole mount stage 15 embryos immunostained (red) to detect pH3 after injection of 1 ng Wt skp2 (d), or 1 ng FBox skp2 (e) mRNA, along with ßgal mRNA as a lineage tracer, in one blastomere at the two cell stage. Dorsal views with injected side to the right. (d',e') Detail of pH3-positive cells on the injected side relative to the uninjected side (boxed area in (d,e), dashed line is dorsal mid-line separating injected and uninjected halves). (f) Embryos were injected with 250 pg, 500 pg or 1 ng Wt skp2 mRNA (n = 41, 83, 87 embryos, respectively) in one blastomere at the two cell stage. Embryos were analyzed for expression of nßt mRNA at stage 15. Data shown in (f) are the percentages of embryos with no change, or moderate or substantial reduction of nßt positive cells on the injected side relative to the uninjected side for each injection (see Additional file 1 for photographs of representative embryos).