Transcriptional repression of human cad gene by hypoxia inducible factor-1α

Ko Fan Chen, Yen Yu Lai, H. Sunny Sun, Shaw Jenq Tsai

Research output: Contribution to journalArticlepeer-review

66 Citations (Scopus)


De novo biosynthesis of pyrimidine nucleotides provides essential precursors for DNA synthesis and cell proliferation. The first three steps of de novo pyrimidine biosynthesis are catalyzed by a multifunctional enzyme known as CAD (carbamoyl phosphate synthetase-aspartate carbamoyltransferase-dihydroorotase). In this work, a decrease in CAD expression is detected in numerous cell lines and primary culture human stromal cells incubated under hypoxia or desferrioxamine (DFO)-induced HIF-1α accumulation. A putative hypoxia response element (HRE) binding matrix is identified by analyzing human cad-gene promoter using a bioinformatic approach. Promoter activity assays, using constructs harboring the cad promoter (-710/+122) and the -67/HRE fragment (25-bases), respectively, demonstrate the suppression of reporter-gene expression under hypoxia. Suppression of cad-promoter activity is substantiated by forced expression of wild-type HIF-1α but abolished by overexpression of dominant-negative HIF-1α. A chromatin immunoprecipitation assay provides further evidence that HIF-1α binds to the cad promoter in vivo. These data demonstrate that the cad-gene expression is repressed by HIF-1α, which represents a functional link between hypoxia and cell-cycle arrest.

Original languageEnglish
Pages (from-to)5190-5198
Number of pages9
JournalNucleic acids research
Issue number16
Publication statusPublished - 2005

All Science Journal Classification (ASJC) codes

  • Genetics


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