OVER-EXPRESSION OF THE 18 KD AND 21 23 KD FIBROBLAST GROWTH FACTOR-2 ISOFORMS IN PC12 CELLS AND SCHWANN-CELLS RESULTS IN ALTERED CELL MORPHOLOGY AND GROWTH/

Basic fibroblast growth factor (FGF-2) occurs in different isoforms wh ich represent alternative translation products from a single mRNA. The question of whether the presence of multiple FGF-2 isoforms has physi ological implications is compelling but unresolved so far. However, it has been shown recently that the FGF-2 isoforms are differentially re gulated in sensory ganglia and peripheral nerve following nerve injury and, moreover, in the adrenal medulla during postnatal development an d after hormonal stimuli suggesting that the isoforms may serve differ ent physiological functions. To investigate isoform-specific effects w e have established immortalized Schwann cells and PC12 cells stably ov er-expressing the 18 kD and the HMW isoforms. We found that the over-e xpression of the different isoforms alters morphology and growth of th e Schwann cells. PC12 cells over-expressing the 18 kD FGF-2 were found to differentiate towards the neuronal phenotype whereas over-expressi on of the HMW isoforms resulted in a stabilization of the endocrine ph enotype, Taken together, these data corroborate the idea of FGF-2 isof orm-specific functions. (C) 1998 Elsevier Science B.V. All rights rese rved.