|
Fig. 5 Coordinate induction of chd and repression of bmp2b by FGFs. (A-X) ichabod embryos injected with 1 pg FGF3 (G-I,S-U) or 0.1 pg FGF8 (J-L,V-X) were compared with uninjected ichabod (D-F,P-R) and wild-type embryos (A-C,M-O) for chd (A-L) or bmp2b (M-X) expression. Thirty percent epiboly and 50% epiboly embryos are shown in animal pole views; 70% epiboly embryos are shown in lateral views, with dorsal to the right in those embryos with a recognizable dorsal side. In every case of chd induction there was also repression of bmp2b [induction and repression of these genes in 30% epiboly embryos after injection with FGF8 RNA (J,V) is indicated with arrowheads]. Thirty percent epiboly embryos after injection with FGF3 RNA, the one condition that did not result in chd induction (compare D,G), also did not show bmp2b repression (compare P,S). (A'-E') ichabod embryos injected with 1 pg (C',E') or 50 pg (D`F') of FGF3 RNA were compared with uninjected ichabod (B') or wild-type (A') embryos for bmp2b expression at 30% epiboly (shown in animal pole views). The lower amount of FGF RNA did not lead to repression of bmp2b but the higher amount of FGF3 RNA did repress the gene. Co-injection of MOchd (E',F') did not affect the level of bmp2b expression at either RNA input (compare C',E' or D`F').