Transient expression of CYP1A1 in rat epithelial cells cultured in suspension

S. A. Monk, M. S. Denison, R. H. Rice

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Suspension of human epidermal cells in methylcellulose-containing medium induces CYP1A1 by a mechanism requiring functional Ah receptor (AhR). In present work CYP1A1 mRNA was induced in a variety of cultured rat epithelial cells by suspension, but the induction was transient, with CYP1A1 mRNA reaching maximal levels by 5 h and disappearing by 12 h. Though the methylcellulose itself contained no detectable ligand, (a) suspension activated the AhR, as judged by mobility shift assays, (b) the AhR competitive inhibitor α-naphthoflavone inhibited suspension-mediated induction, and (c) induction was dependent upon dioxin responsive transcriptional elements in the CYP1A1 promoter. The rapid disappearance of CYP1A1 mRNA after 5 h of suspension was unaffected by the addition of TCDD but was prevented by the inclusion of the protein synthesis inhibitor cycloheximide. Thus the downregulation appears to be mediated by a novel short-lived protein induced or activated by suspension.

Original languageEnglish (US)
Pages (from-to)154-162
Number of pages9
JournalArchives of Biochemistry and Biophysics
Issue number1
StatePublished - Sep 1 2001


  • Ah receptor
  • CYP1A1
  • Keratinocytes
  • Methylcellulose

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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