Expression of the fibroblast growth factor-2 gene during chick development.

In this report, we have carried out mRNA in situ hybridization analysis to study the pattern of expression of the fibroblast growth factor-2 (FGF-2) gene during chick development. The expression pattern of FGF-2 was compared to that of the fibroblast growth factor-1 (FGF-1) gene to further assess a possible role of the FGF-2 during chick embryogenesis. The whole embryos of various stages were examined with 35S-labeled riboprobes transcribed from the coding regions of chick FGF-2 and FGF-1 cDNAs. We show that the distribution pattern of FGF-2 mRNA was highly specific. The FGF-2 transcripts were localized to limb mesenchymes, pharyngeal regions, and embryonic kidneys in day 3 to day 6 chick embryos. However, no FGF-1 mRNA was detected in these structures indicating a unique role of FGF-2 in chick development. These results support the hypothesis that FGF-2 may be a crucial signaling molecule during chick embryogenesis.