cDNA cloning, heterologous expression, and characterization of mouse CYP2G1, an olfactory-specific steroid hydroxylase

Zichun Hua, Qing yu Zhang, Ting Su, Thomas W. Lipinskas, Xinxin Ding

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

CYP2G1 is expressed specifically in the olfactory mucosa in rabbits and rats. In the present study, a full-length cDNA for mouse CYP2G1 was obtained using a PCR approach with RNA preparations from the olfactory mucosa of C57BL/6 mice. Sequence comparisons indicated that mouse CYP2G1 is highly homologous in deduced amine acid sequence to rabbit (82.4% identity) and rat CYP2G1 (94.9% identity). RNA blot and immunoblot analyses indicated that mouse CYP2G1 is expressed only in the olfactory mucosa. The coding region of the mouse CYP2G1 cDNA was cloned into a baculoviral expression vector for heterologous production of the enzyme in cultured insect cells. Heterologously expressed mouse CYP2G1 was active in a reconstituted system toward testosterone and progesterone, producing all the major metabolites detected in olfactory microsomal reactions, including 15α-, 15β-, and 2β- hydroxytestosterone from testosterone and two unidentified metabolites from progesterone. Kinetic analysis indicated that mouse CYP2G1 has relatively high affinities toward the steroid substrates, with K(m) values in the micromolar range for both testosterone and progesterone. At a substrate concentration of 10 μM, microsomes of olfactory mucosa had much higher turnover numbers toward testosterone and progesterone than hepatic microsomes, consistent with the olfactory-specific expression of a high- affinity sex steroid hydroxylase. These findings will facilitate further molecular genetics studies on the biological function of CYP2G1 in a mouse model.

Original languageEnglish (US)
Pages (from-to)208-214
Number of pages7
JournalArchives of Biochemistry and Biophysics
Volume340
Issue number2
DOIs
StatePublished - Apr 15 1997
Externally publishedYes

Keywords

  • CYP2G1
  • cDNA cloning
  • heterologous expression
  • mouse
  • olfactory mucosa
  • steroid hormone
  • steroid metabolism

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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