Transcriptional Regulation of the Rat Vascular Endothelial Growth Factor Gene by Hypoxia

doi:10.1074/jbc.270.22.13333

Transcriptional Regulation of the Rat Vascular Endothelial Growth Factor Gene by Hypoxia (*)

From the (1) Cardiology Division and
(2) Hematology-Oncology Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115

^§ To whom correspondence and reprint requests should be addressed:
Brigham and Women's Hospital, LMRC Rm. 222, 221 Longwood Ave., Boston, MA 02115
. Tel.: 617-732-7646; Fax: 617-739-0748.

Abstract

Vascular endothelial growth factor (VEGF), a potent angiogenic factor and endothelial cell-specific mitogen, is up-regulated by hypoxia. However, the mechanism(s) responsible for hypoxic induction of VEGF has not been clearly delineated. We report that the steady state VEGF mRNA levels are increased 12 ± 0.6-fold, but the transcriptional rate for VEGF is increased only 3.1 ± 0.6-fold by hypoxia in PC12 cells. In order to investigate cis-regulatory sequences which mediate this response to hypoxia, we cloned the rat genomic sequences encoding VEGF and identified a 28-base pair element in the 5′ promoter that mediates hypoxia-inducible transcription in transient expression assays. This element has sequence and protein binding similarities to the hypoxia-inducible factor 1 binding site within the erythropoietin 3′ enhancer. Post-transcriptional mechanisms have also been suggested to play a role in the hypoxic induction of VEGF. Evidence is provided that a frequently used polyadenylation site is 1.9 kilobases downstream from the translation termination codon for rat VEGF. This site is 1.5 kilobases further downstream from the polyadenylation site previously reported for VEGF. This new finding reveals sequence motifs in the 3′-untranslated region that may mediate VEGF mRNA stability.

Footnotes

↵* This work was supported by National Institutes of Health Grants T32HL07604 (to A. P. L.), 1F32HL08838-02 (to N. S. L.), and DK45098 (to M. A. G.), an American Heart Association Established Investigator award (to M. A. G.), and an American Heart Association grant-in-aid (to M. A. G.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank/EMBL Data Bank with accession number(s) U22372 and U22373.
↵¹ The abbreviation used are:

VEGF

vascular endothelial growth factor

Epo

erythropoietin

HIF-1

hypoxia-inducible factor 1

SSC

sodium saline citrate

SV40

simian virus 40

TBE

Tris borate EDTA

AP-1

activator protein 1

AP-2

activator protein 2

bp

base pair(s)

kb

kilobase(s)

UTR

untranslated region

EMSA

electromobility shift assay.
↵²A. P. Levy, N. S. Levy, and M. A. Goldberg, unpublished observations.