Repression of Human Fibroblast Growth Factor 2 by a Novel Transcription Factor

Here we describe the cloning of the regulator of fibroblast growth factor 2 (FGF-2) transcription (RFT) using a yeast one-hybrid screening with a defined motif in FGF-2 promoter as a target sequence. Overexpression of human RFT (RFT-A) reduces FGF-2 RNA and protein levels in both normal and tumor cell lines. Its splice variants, RFT-A' and RFT-B, have deletions in the putative DNA binding domain and fail to bind FGF-2 promoter and repress FGF-2 gene expression. The ratios of RFT isoforms differ between normal and tumor cells, with the splice variants dominating in tumor cells. Overexpression of RFT-A induces glioma cell death. Our data suggest that regulation of FGF-2 by RFT is important for cellular functions and may be impaired in certain tumors.