Identification and characterization of the promoter of fibroblast activation protein.
Fibroblast activation protein (FAP) is a type II integral membrane glycoprotein belonging to the serine protease family. It is selectively expressed by tumor stromal fibroblasts and transiently in the fibroblasts of healing wounds. FAP has been shown to modulate growth, differentiation, adhesion, and metastasis of tumor cells. Despite the importance of FAP in cancer, the mechanisms that govern its expression have not been defined. In this study, we determined the transcription start site of the FAP gene and identified a 2-kb segment with promoter activity in cells expressing FAP. Truncation of this fragment revealed that the core promoter activity resided in a 245-bp fragment surrounding the transcription start site. Electrophoretic mobility shift assay showed that EGR1 binds to the FAP promoter. Mutation of the EGR1 site within this fragment significantly decreased the promoter activity of FAP and eliminated EGR1 binding. Down-regulation of EGR1 resulted in a significant reduction in endogenous FAP mRNA expression. These findings identify the basal transcriptional requirements of FAP gene expression and show EGR1 is an important regulator of FAP expression.
Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
Jiping
J
Zhang
Matthildi
M
Valianou
Jonathan D
JD
Cheng
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004247:DNA; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D010450:Endopeptidases; D018093:Gelatinases / Q000235:genetics*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D012697:Serine Endopeptidases / Q000235:genetics*; D014158:Transcription, Genetic; D000099167:Fibroblast Activation Protein Alpha
D004247:DNA; D017931:DNA Primers; D010450:Endopeptidases; D018093:Gelatinases; D008565:Membrane Proteins; D012697:Serine Endopeptidases; D000099167:Fibroblast Activation Protein Alpha