VEGFR-3 promoter characterization and gene expression in lymphatic endothelial cells. (A) VEGFR-3 mRNA expression and (B) full-length VEGFR-3−849/+55 promoter activity were measured in the lymphatic endothelial cell lines RLECs, H-LLY, and HDLECshtert. Human lung blood microvascular endothelial cell line, HULEC, was used as a VEGFR-3–negative cell line. Data shown are a representative image of VEGFR-3 transcript expression of 3 independent experiments (A) and the mean promoter activity of 3 independent experiments ± SEM (B). **P < .01 versus VEGFR-3 promoter activity in the negative control cell line HULEC as determined by Student unpaired t test. (C) Activities of VEGFR-3 promoter deletion constructs were tested in RLECs, H-LLY, and HDLECshtert. The left panel shows schematic illustration of deletion constructs with relative locations of predicted transcription factor binding sites. The right panel shows VEGFR-3 promoter activity of deletion constructs presented as relative light units per second (RLU/S) normalized per renilla luciferase activity of cotransfected thymidine kinase (TK)–renilla plasmid. Experiments were performed in duplicate and reproduced at least 3 times. Data are presented as the mean promoter activity of 3 independent experiments ± SEM.
