Figure 7.

EphA4 Y928F induces expression of eFGF, FGF-8, FGFR1, and FGFR4a. (A and B) Embryos were left uninjected or injected with Y928F mRNA (1 ng/embryo for A; 0.125 ng or 0.5 ng for B) into both blastomeres at the 2-cell stage. Animal caps were excised at stage 8 and cultured until stage 26 (A) or stage 10.5/11 (B). Expression of eFGF and FGF-8 were analyzed by RT-PCR. EF-1α was used to normalize cDNAs as a control. PCR reactions were performed in the absence of reverse transcriptase [RT(-)] as a negative control. A reaction performed using stage 26 (A) or stage 11 (B) whole embryo [WE RT (+)] RNA served as a positive control. (C) Analysis of ectopic protrusions by whole mount in situ hybridization of stage 26/28 embryos. Embryos left uninjected or injected with Y928F mRNA (2.5 ng/embryo) were fixed and probed with DIG-labeled FGF-8 (top three embryos), FGFR1 (middle three embryos), or FGFR4a (bottom three embryos). Arrowheads indicate staining of ectopic protrusions by the indicated probes.