Fig. 2. Induction of both cell proliferation and expression of FoxM1 and its target G2-M cell-cycle regulators by BMP inhibition. (A) Animal caps were isolated from late blastula Xenopus embryos (st. 9) pre-injected with Noggin mRNA (100 pg) or Wnt8 mRNA (100 pg) at the one-cell stage; for FGF signaling, animal caps (from uninjected embryos) were treated with bFGF (100 ng/ml). The animal caps were cultured until sibling control embryos reached st. 20 and were then analyzed by RT-PCR (upper panel) or immunoblotting (lower panel). N-CAM, Xbra and M-actin are downstream markers of Noggin, FGF and Wnt, respectively. (B) Embryos pre-injected with lacZ mRNA (100 pg) together with or without dnBMPR mRNA (500 pg) at one animal-ventral blastomere at the eight-cell stage were cultured until st. 14. Embryos were then processed and analyzed as in Fig. 1B, except that the numbers of pH3-positive cells on the injected (β-Gal, light blue) and uninjected sides of the ventral region (the area boxed in red) were counted. ^*P<0.01. (C) Animal caps from the late blastula embryos pre-injected with Noggin mRNA (100 pg) and either control MO or FoxM1-MO (36 ng) at the one-cell stage were cultured as in A and analyzed by RT-PCR (upper panel) or immunoblotting (lower panel). (D) Animal caps pre-treated with Noggin mRNA (100 pg) or FoxM1(N) mRNA (1 ng) were processed as in C.