Study On The Basal And Regulatory Activity Of Human PDGFR Promoter

Objetives:Platelet-Derived Growth Factor Receptor(PDGFR) plays an important role in Angiogenesis. However, the mechanisms by which PDGFR expression is regulated remains poorly understood. In this study, we focused on the basal as well as regulatory activity of human PDGFR promoter.Methods:Firstly, the human PDGFR genes and their promoters were analyzed by bioinformatics. Secondly, the up promoter element (UPE) of human PDGFRs were studied by Dual-Luciferase reporter system. Thirdly, EMSA assay was used to search the specific transcription factors responsible for the promoter activity. Finally, the regulatory activity of human PDGFR promoters by bFGF was investigated.Results:Three highly conserved regions were found within the promoter of human PDGFR-a as well as PDGFR-β. And C/EBPb,OCT-1,GATA-1 and SP-1 transcription factors binding cites were found in the region(-646/+308) of PDGFR-a gene, whereas AP-1/C-JUN/C-FOS,LMO-2/GATA-3,OCT-1 transcription factors binding cites in the conserved regions of PDGFR-βgene. With luciferase activity assays, it was demonstrated that there was no obvious transcription activity in the region(-2 603/+422) of PDGFR-a gene, however, two regions (-246/+53) and (+840/+1083) were identified to regulate human PDGFR-βpromoter transcription. The former region performed a positive regulation of PDGFR-βpromoter transcription, while the latter played a negative role. The results of EMSA indicated that the predicted transcription factors could specifically bind to nuclear factors. bFGF upregulated PDGFR-a and PDGFR-β4.1-fold and 2.6-fold respectively in ECV304 cells, on the other hand, in HUVEC cells bFGF downregulated PDGFR-a and PDGFR-p 6.2-fold and 2.6-fold respectively. There was no regulatory elements responses to bFGF induction within the region we studied. Conclusions:The region (-2 603/+422) of PDGFR-a gene have no obvious transcription activity, however, two regions (-246/+53) and (+840/+1083) were identified to regulate human PDGFR-(3 promoter transcription. The former region performed a positive regulation of PDGFR-βpromoter transcription, while the latter played a.negative role; bFGF could upregulated PDGFR in ECV304 cells but downregulated PDGFR in HUVEC cells; the promoter of human PDGFR-αand PDGFR-βgene what we have cloned have no regulatory elements responses to bFGF induction.