Fig. 7. XMeis3-antimorph protein anteriorizes neural marker expression in animal cap explants caudalized by bFGF or Wnt3a. (A) One-cell stage embryos were injected in the animal hemisphere with 1.6 ng of XMeis3-AM RNA (lane 4) or 0.2 ng of noggin RNA (lane 5) or both (lane 6). Eighteen animal cap explants were removed from uninjected (lanes 2-3) and injected groups of blastula embryos (stage 8-9). Explants from each group were aged until stage 10.25 and XbFGF was added at 50 ng/ml. Explants from each group were grown to late neurula stage and total RNA was isolated. RT-PCR analysis was performed with the markers: En2 and HoxB9. EF1 served as a control for quantifying RNA levels in the different samples. -RT-PCR (lane 1) was performed on total RNA isolated from uninjected embryos. (B) One-cell stage embryos were injected in the animal hemisphere with 1.6 ng of XMeis3-AM RNA (lane 6-7 and 9), 0.2 ng of noggin RNA (lane 4 and 8-9) and/or 0.1 ng of mouse Wnt3a RNA (lanes 5, 7-9). Eighteen animal cap explants were removed from uninjected (lane 3) and injected groups of blastula embryos (stage 8-9). Explants from each group were grown to late neurula stage and total RNA was isolated. In parallel, total RNA was also isolated from uninjected control embryos (lanes 1-2). RT-PCR analysis was performed with the markers En2, Krox20, HoxB3 and HoxB9. EF1 served as a control for quantifying RNA levels in the different samples. For controls, RT-PCR (lane 2) and -RT-PCR (lane 1) were performed on total RNA isolated from uninjected control embryos.