Figure 4

Quail-chick chimera tip cell streak transplants. (A-C) Caudal quail streak cells transplanted to the chick rostral tip of the streak at stage 3d (A-0h, arrowed) and incubated for 22 hours in EC culture, labeled with QCPN antibody to identify donor quail cells (B). Quail cells in rostral head of whole mount embryo at stage 10. Line indicates level of transverse section (C), 50 μm gelatin section through head with QCPN positive cells maintaining their mesoderm fate. (C' and C") High magnification (10x) images of quail cells from C, with and without Hoffman modulation contrast optics, respectively. Transplanted cells maintain their mesodermal fate (arrowhead) and are mostly excluded from the foregut and endoderm (arrowed). (D-F) Quail rostral streak "tip" cells transplanted into chick mid-streak (D, arrowed, 0 h). (E) Cells migrate laterally after 22 hours of incubation (stage 12 whole mount embryo). Black line indicates level of transverse section F. The donor quail cells maintain their endodermal fate (arrowed), with a few mesoderm cells found in the intermediate mesoderm (arrow).