A delayed-early gene activated by fibroblast growth factor-1 encodes a protein related to aldose reductase.

The addition of polypeptide mitogens to quiescent cell lines induces the expression of various gene products, some of which are likely to perform functions critical for cell cycle progression, DNA synthesis, and mitosis. We have used a differential display approach to identify fibroblast growth factor (FGF)-1-inducible genes in NIH-3T3 cells. One of these genes, termed FGF-regulated (FR)-1, encodes a 316-amino acid protein with approximately 82% amino acid sequence identity to an abundant protein expressed in mouse vas deferens and approximately 70% identity to human aldose reductase. The function of the vas deferens protein is unknown; however, aldose reductase is an NADPH-dependent monomeric oxidoreductase implicated in the pathogenesis of diabetic complications. FGF-1 induction of FR-1 mRNA expression is first detectable at 4 h after mitogen addition and is dependent on de novo RNA and protein synthesis. FGF-2 or phorbol ester treatment can also increase FR-1 mRNA levels; in contrast, whole blood serum or individual growth factors present in serum have only minimal effects on FR-1 mRNA expression. FR-1 mRNA is detectable in a number of mouse tissues but is most abundant in newborn liver and in adult intestine, ovary, and testis. These results raise the possibility that aldose reductase-related proteins may play a role in FGF-1- and FGF-2-stimulated mitogenesis.