Vascular endothelial growth factor receptor-2: counter-regulation by the transcription factors, TFII-I and TFII-IRD1

J Biol Chem. 2005 Aug 19;280(33):29856-63. doi: 10.1074/jbc.M500335200. Epub 2005 Jun 7.

Abstract

The vascular endothelial growth factor receptor-2 (VEGFR-2/KDR/flk-1) functions as the primary mediator of vascular endothelial growth factor activation in endothelial cells. Regulation of VEGFR-2 expression appears critical in mitogenesis, differentiation, and angiogenesis. Transcriptional regulation of the VEGFR-2 is complex and may involve multiple putative upstream regulatory elements including E boxes. Transcript initiation is dependent on an initiator (Inr) element flanking the transcriptional start site. The transcription factor, TFII-I, enhances VEGFR-2 transcription in an Inr-dependent fashion. TFII-I is unusual both structurally and functionally. The TFII-I transcription factor family members contain multiple putative DNA binding domains. Functionally, TFII-I acts at both the basal, Inr element as well as at several distinct upstream regulatory sites. It has been postulated that the structure of TFII-I might allow simultaneous interaction with both basal and regulatory sites in a given promoter. As TFII-I is known to act at regulatory sites including E boxes as well as at the basal Inr element, we evaluated the possibility of Inr-independent TFII-I activation of the VEGFR-2 promoter. We found that an Inr-mutated VEGFR-2 reporter construct retains TFII-I-stimulated activity. We demonstrated that TFII-I binds to both the Inr and to three regulatory E boxes in the human VEGFR-2 promoter. In addition, reduction in TFII-I expression by siRNA results in decreased VEGFR-2 expression. We also describe counter-regulation of the VEGFR-2 promoter by TFII-IRD1. We found that TFII-I is capable of acting at both basal and regulatory sites in one promoter and that the human VEGFR-2 promoter is functionally counter-regulated by TFII-I and TFII-IRD1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Cattle
  • Cells, Cultured
  • Gene Expression Regulation*
  • Humans
  • Molecular Sequence Data
  • Muscle Proteins / physiology*
  • Nuclear Proteins / physiology*
  • Promoter Regions, Genetic
  • RNA, Small Interfering / pharmacology
  • Trans-Activators / physiology*
  • Transcription Factors, TFII / physiology*
  • Vascular Endothelial Growth Factor Receptor-2 / genetics*

Substances

  • GTF2I protein, human
  • GTF2IRD1 protein, human
  • Muscle Proteins
  • Nuclear Proteins
  • RNA, Small Interfering
  • Trans-Activators
  • Transcription Factors, TFII
  • Vascular Endothelial Growth Factor Receptor-2