Fig. 6. B-line secondary notochord induction. (A-H) bFGF and BMP-4 cooperate to induce B-line notochord. (A-D) Bright field view. (E-H) Immunofluorescence for Not-1 antigen. (A,E) BSA-treated control B6.2 blastomere. Upon this treatment, all constituent cells develop into large muscle cells (Kim and Nishida, 1999). (B,F) BMP-4 protein treatment. (C,G) bFGF protein treatment. Upon this treatment, all constituent cells develop into small mesenchyme cells (Kim et al., 2000). (D,H) Simultaneous treatment with bFGF and BMP-4 proteins. Four notochord cells were induced in the partial embryo. (I-K) Unequal cleavage of B7.3. When B7.3 was isolated at the 44-cell stage, the cleavage was equal and produced daughter cells of similar size (I). Treatment with BMP-4 protein provoked a slightly unequal cleavage (J), similar to that observed when B7.3 was isolated at the late 64-cell stage (K). Scale bars: 50 µm.
