A unique bFGF-responsive transcriptional element

The mitogen-regulated protein/proliferin (mrp/plf) genes encode closely related proteins that stimulate cell proliferation and angiogenesis. Basic fibroblast growth factor (bFGF) increases mrp/plf mRNA and protein production by 3T3 cells. Although the three cloned mrp/plf gene promoters are over 97% identical, only mrp3 is transcriptionally activated by bFGF. A series of truncated mrp3 promoter sequences were tested to determine the minimal promoter sequence necessary for bFGF-responsive transcription. Within the minimal bFGF-responsive mrp3 promoter fragment, a putative FGF-regulatory element (FRE) was identified. Nuclear factors that bind the FRE are present in 3T3 cells. When present upstream of a thymidine kinase basal promoter, the FRE exhibits high transcriptional activity and responds to bFGF. Thus, the FRE is a strong transcriptional element that is regulated by bFGF and that may participate in regulating the mrp3 gene and perhaps other FGF-regulated genes. (C) 1999 Elsevier Science B.V. All rights reserved.