Molecular cloning of the human platelet-derived growth factor receptor β (PDGFR-β) promoter and drug targeting of the g-quadruplex-forming region to repress PDGFR-β expression

Yong Qin, Jessica S. Fortin, Denise Tye, Mary Gleason-Guzman, Tracy A. Brooks, Laurence H. Hurley

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

To understand the mechanisms controlling platelet-derived growth factor receptor β (PDGFR-β) expression in malignancies, we have cloned and characterized the first functional promoter of the human PDGFR-β gene, which has been confirmed by luciferase reporter gene assays. The transcription initiation sites were mapped by primer extension. Promoter deletion experiments demonstrate that the proximal, highly GC-rich region (positions -165 to -139) of the human PDGFR-β promoter is crucial for basal promoter activity. This region is sensitive to S1 nuclease and likely to assume a non-B-form DNA secondary structure within the supercoiled plasmid. The G-rich strand in this region contains a series of runs of three or more guanines that can form multiple different G-quadruplex structures, which have been subsequently assessed by circular dichroism. A Taq polymerase stop assay has shown that three different G-quadruplex-interactive drugs can each selectively stabilize different G-quadruplex structures of the human PDGFR-β promoter. However, in transfection experiments, only telomestatin significantly reduced the human PDGFR-β basal promoter activity relative to the control. Furthermore, the PDGFR-β mRNA level in Daoy cells was significantly decreased after treatment with 1 μM telomestatin for 24 h. Therefore, we propose that ligand-mediated stabilization of specific G-quadruplex structures in the human PDGFR-β promoter can modulate its transcription.

Original languageEnglish (US)
Pages (from-to)4208-4219
Number of pages12
JournalBiochemistry
Volume49
Issue number19
DOIs
StatePublished - May 18 2010

ASJC Scopus subject areas

  • Biochemistry

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