Identification of a novel transcriptional silencer in the protein-coding region of the human CYP2 C9 gene

Shi Hua Xiang, Holly K. Parsons, Michael Murray

Research output: Contribution to journalArticle

10 Scopus citations


A novel regulatory element (27 bp) which confers transcriptional repression was identified within the protein-coding region immediately after the translation start codon in the human cytochrome P450 (CYP) 2C9 gene. Deletion of this element increased transcriptional activity in HepG2 cells by transient transfection assay. Nuclear protein extracts from HepG2 cells and human liver were found in electrophoretic mobility shift assays to bind specifically to the 27 bp element. A putative binding protein was partially purified by DNA-affinity chromatography and was determined by Southwestern blotting to have a molecular weight of approx. 100 kDa. Studies with mutated competitor oligonucleotides established that binding of the nuclear protein to the 27 bp cis-element was dependent upon two 6 bp direct repeats (5'-CTTGTG-3') that were separated by three bases. It is possible that this novel cis-acting element may be involved in the negative regulation of CYP2C9.

Original languageEnglish (US)
Pages (from-to)123-129
Number of pages7
Issue number1-2
Publication statusPublished - Mar 16 1998



  • Cis-acting element
  • Cytochrome P450
  • Gene expression
  • Trans-acting factor

ASJC Scopus subject areas

  • Genetics

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