Fig. 5.

Stage 6 primitive streak cells can differentiate into duct tissue if placed into a duct-forming region. (A-H) Stage 6 mid-primitive streak was labeled with DiI and grafted into the equivalent region of stage 6 (A-D) or stage 4 (E-H) embryos. The control grafts migrated to positions posterior to the normal duct forming region (B, arrow indicates somite 10), whereas when transplanted into stage 4 embryos the graft cells reached the duct-forming region (F; arrow indicates somite 10). Embryos were sectioned and stained for Lim1 (C,G, green), the quail marker QCPN (C,G, red) and DAPI (D,H). Grafts transplanted into stage 4 embryos (E-H) differentiated into Lim1-expressing duct tissue, in contrast to the controls grafted into stage 6 embryos (A-D). c, nephrogenic cord; d, nephric duct; lp, lateral plate; nt, neural tube; som, somite.