Biosynthesis of human fibroblast growth factor-5.
We have analyzed the biosynthesis of human fibroblast growth factor-5 (FGF-5) at the translational and posttranslational levels. FGF-5 RNA synthesized in vitro can be translated in rabbit reticulocyte lysates to yield a 29,500-Da protein, which is consistent with the molecular weight predicted from the coding sequence. The efficiency of FGF-5 translation is dramatically enhanced if an upstream open reading frame (ORF-1) in the RNA is deleted or if both AUG codons in ORF-1 are destroyed by point mutations, while partial enhancement is achieved by individual mutation of either ORF-1 AUG codon. These data suggest that FGF-5 synthesis requires the scanning of ribosomes past the two ORF-1 AUG codons. The introduction of these ORF-1 mutations into a eukaryotic FGF-5 expression vector increases its capacity to transform mouse NIH 3T3 cells up to 50-fold upon transfection. FGF-5 is secreted from transfected 3T3 cells and from human tumor cells as glycoproteins containing heterogeneous amounts of sialic acid. Glycosidase treatments suggest that the growth factor bears both N-linked and O-linked sugars.
Bates
B
B
Department of Biochemistry and Molecular Biophysics, Columbia University College of Physicians and Surgeons, New York, New York 10032.
Hardin
J
J
Zhan
X
X
Drickamer
K
K
Goldfarb
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D016366:Open Reading Frames; D014176:Protein Biosynthesis; D011817:Rabbits; D014162:Transfection; D014407:Tumor Cells, Cultured
C496449:FGF5 protein, human; C496450:Fgf5 protein, mouse; D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors