Fig. 6. RyR expression in early chick. (A-F) Antibodies directed against all three RyR isoforms. Symmetric signal is detected around Hensen's node at HH4 (arrows; B,D). RyR signal expands into the primitive streak at HH5 (left arrow, E) and neural plate by HH6 (arrows, F). Signal was absent from embryos reacted with irrelevant antibody (A,C). Images are dorsal views with anterior at the top.