A cDNA encoding fish fibroblast growth factor-2, which lacks alternative translation initiation.
Here, we describe the isolation of a rainbow trout cDNA clone that contains the entire fibroblast growth factor-2 (FGF-2; basic FGF) coding region. Interestingly, the rainbow trout cDNA contains a translation stop codon just upstream of the primary initiating methionine codon and so cannot give rise to the longer forms of FGF-2 that are produced in mammals by alternative translation initiation at leucines farther upstream. Transfection of human FGF-2 cDNA into fish cells shows that fish cells can initiate protein synthesis at an upstream leucine CUG codon; surprisingly, however, synthesis is initiated only at the most 5' CUG and not at the two subsequent CUG codons or the methionine AUG codon also used in mammalian cells. Like other FGF-2 proteins, bacterially produced rainbow trout FGF-2 protein binds tightly to heparin-Sepharose and also promotes the proliferation of fibroblast cells. However, the protein differs from all others previously identified at amino acids 121-123, which are part of the proposed highly conserved receptor-binding domain. Comparisons of the efficacies of recombinant wild-type and mutant rainbow trout FGF-2 proteins demonstrate that these three amino acids are critical to the activity of FGF-2.
Hata
J i
Ji
Central Research Laboratory, Nippon Suisan Kaisha Limited, 559-6 Kitanomachi, Hachioji, Tokyo 192, Japan.
Takeo
J
J
Segawa
C
C
Yamashita
S
S
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D016222:Fibroblast Growth Factor 2 / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss; D010442:Peptide Chain Initiation, Translational / Q000235:genetics*; D014176:Protein Biosynthesis; D016415:Sequence Alignment
D018076:DNA, Complementary; D016222:Fibroblast Growth Factor 2