Structure and expression of the mRNA encoding a novel fibroblast growth factor, FGF-18.
We isolated the cDNA encoding a novel member (207 amino acids) of the fibroblast growth factor (FGF) family from rat embryos. Because this protein is the 18th documented member of the FGF family, we tentatively termed it FGF-18. We have also determined mouse and human FGF-18 with high amino acid identity (99.5 and 99.0%) to rat FGF-18, respectively. Among FGF family members, FGF-18 is most similar (52.7% amino acid identity) to FGF-8 and FGF-17. FGF-18 has a typical signal sequence at its amino terminus. Recombinant rat FGF-18, which was efficiently secreted by High Five insect cells infected with recombinant baculovirus containing the cDNA, induced neurite outgrowth in PC12 cells. The expression of FGF-18 mRNA was examined in adult rat tissues and embryos by Northern blotting analysis and in situ hybridization. FGF-18 mRNA of approximately 2. 7 kilobases was preferentially detected in the lung among adult rat tissues examined. In rat embryos, FGF-18 mRNA was detected in several discrete regions at embryonic days 14.5 and 19.5 but not at E10.5. The temporal and spatial patterns of FGF-18 mRNA expression in embryos are quite different from those of FGF-8 and FGF-17 mRNAs reported. The present results indicate that FGF-18 is a unique secreted signaling molecule in the adult lung and developing tissues.
Ohbayashi
N
N
Department of Genetic Biochemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo, Kyoto 606-8501, Japan.
Hoshikawa
M
M
Kimura
S
S
Yamasaki
M
M
Fukui
S
S
Itoh
N
N
D000595:Amino Acid Sequence; D000818:Animals; D019143:Evolution, Molecular; D005346:Fibroblast Growth Factors / Q000235:genetics*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016716:PC12 Cells; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism*; D051381:Rats
C484724:FGF17 protein, human; C484726:Fgf17 protein, mouse; C111253:Fgf17 protein, rat; D012333:RNA, Messenger; C113569:fibroblast growth factor 18; D005346:Fibroblast Growth Factors