THE FGF-4 PROMOTER IS REQUIRED FOR TRANSFORMATION AND IS ACTIVE IN BOTH EMBRYONAL AND SOMATIC-CELLS

We report the independent isolation of a rearranged FGF-4 gene from a patient with chronic myeloid leukaemia We show that the FGF-4 gene has been truncated 30 nucleotides 3' to the coding sequence and has been fused to the RNA processing signals from a putative unknown gene on ch romosome 15. We demonstrate that the promoter region of the FGF-4 gene is active in NIH3T3 cells and is indeed necessary for transformation. Using the luciferase reporter assay we have shown that the FGF-4 5' f lanking sequences possess easily detectable promoter activity in both F9 and HeLa cell lines. 5' deletion analysis of the FGF-4 promoter has delineated regions containing cis-acting elements of functional impor tance. These regulatory regions are common to both embryonal and somat ic cell lines. Electrophoretic mobility shift assay, using nuclear ext racts from F9 and HeLa cells, has allowed detection of DNA-protein int eractions occurring in the functionally significant regions. Subsequen t comparison of the human and murine FGF-4 promoters show that the reg ions of functional significance are highly conserved. We suggest that the FGF-4 gene may be suppressed through a distal suppressor locus and becomes active when separated from this suppressor.