Figure 6.

Transient expression of COR7b in the notochord. Coronal sections of the notochord at stage 12 (A), 16 (B), 19 (C), 24 (D), 27 (E), 29 (F), and 31 (G) were hybridized with antisense RNA probes specific for COR7a or COR7b and with the nonspecific probe COR7ab. Only the signals corresponding to COR7b transcripts obtained with the COR7ab probe are shown. Chicken embryos reach stage 12 after 45–50 hr of incubation, stage 16 after 51–56 hr, stage 19 after 3 days (E3), stage 24 at E4, stage 27 at E5, stage 29 at E6, and stage 31 at E7. COR7b transcripts are detected from stage 16 to stage 29. Note that the COR7b signal intensity reaches a peak at E4. [Bars = 15 μm (A, B, and D) and 34 μm (C and E–G).]