CpG methylation of the mouse CYP1A2 promoter

Bowhan Jin, Duk Woong Park, Ki Whan Nam, Goo Taeg Oh, Yong Soon Lee, Doug Young Ryu

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Cytochrome P450 1A2 (CYP1A2) is a xenobiotic metabolizing enzyme that is tissue-specifically regulated in the mammalian liver by arylhydrocarbon receptor (AhR)-dependent and -independent pathways. In this study, CpG methylation of the CYP1A2 promoter was analyzed in mouse tissues and liver-derived cells. Compared to lung and kidney, the CYP1A2 promoter is undermethylated in the liver in a promoter domain-specific manner. The CYP1A2 promoter showed a similar methylation pattern in wild-type and AhR-null liver. At birth, the promoter was hypermethylated and CYP1A2 was negligibly expressed in the liver. However, CYP1A2 expression increased following birth, coincident with the demethylation of the promoter. In hepatoma Hepa1c1c7 cells not expressing CYP1A2, the promoter was hypermethylated at specific CpG sites. In isolated hepatocytes, CYP1A2 expression declined over time and the degree of CYP1A2 methylation increased, albeit only after a delay. Exposure to 5-aza-2′-deoxycytidine did not induce CYP1A2 in Hepa1c1c7 cells and hepatocytes. Taken together, our findings suggest that CpG methylation is involved in the tissue-specific and developmental regulation of CYP1A2, but the de novo methylation of the CYP1A2 promoter is induced by the silent state of the gene rather than causing it.

Original languageEnglish
Pages (from-to)11-18
Number of pages8
JournalToxicology Letters
Issue number1
StatePublished - 30 Aug 2004

Bibliographical note

Funding Information:
This study was supported in part by the Research Institute for Veterinary Research, Seoul National University, Seoul, Korea. These experiments complied with the currents laws of Korea where they were conducted.


  • 5-aza-2′-deoxycytidine
  • ARNT
  • AhR
  • AzaC
  • Bhlh
  • CYP
  • RT-PCR
  • WME
  • Williams' medium E
  • XRE
  • arylhydrocarbon receptor
  • arylhydrocarbon receptor nuclear translocator
  • basic helix-loop-helix
  • cytochrome P450
  • reverse transcription-polymerase chain reaction


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