TY - JOUR
T1 - Isolation and characterization of a new rat P450 (CYP3A18) cDNA encoding P4506β-2 catalyzing testosterone 6β- and 16α- hydroxylations
AU - Nagata, Kiyoshi
AU - Murayama, Norie
AU - Miyata, Masaaki
AU - Shimada, Miki
AU - Urahashi, Atsushi
AU - Yamazoe, Yasushi
AU - Kato, Ryuichi
PY - 1996
Y1 - 1996
N2 - A cytochrome P450 cDNA, encoding a new form of CYP3A protein, was isolated from a liver cDNA library of a male rat using anti-P4506β-1and anti-P4506β-2 antibodies and the CYP3A2 cDNA. The cDNA (CYP3A18 cDNA) consisted of 1987 nucleotides, in which were contained an open reading frame of 1491 bp (corresponding to 497 amino acids), 5′-(59bp) and 3′-noncoding regions (437 bp). The deduced amino acid sequence of CYP3A18 cDNA was completely identical in the first 27 N-terminal residues of P4506β-2 previously isolated by us (Nagata et al. J Biochem 1990: 107, 718-725) from livers of rats treated with dexamethasone, and also shared higher extents of similarity with hamster CYP3A10 (78.5%) than with rat CYP3As previously sequenced (66.3-69.3%). Northern blot analyses indicated a male-dominant expression of this new CYP3A mRNA and enhanced expression in dexamethasone-or pregnenolone-16α-carbonitrile (PCN)-treated, but not phenobarbital- or 3-methylcholanthrene-treated rats. Expressed CYP3A18 protein in COS-1 cells migrated at a position identical to that of purified P4506β-2 on sodium dodecyl sulfate-acrylamide gel electrophoresis and catalyzed 16β- and 6α-hydroxylations of testosterone. In contrast to CYP3A1 and CYP3A2, cytochrome b5 was not essential for maximal catalytic activities of recombinant CYP3A18 protein. These results, together with ontogenic profiles of CYP3A18 mRNA and P4506β-2 protein, indicate that the newly isolated CYP3A18 cDNA encodes P4506β-2 in rat liver.
AB - A cytochrome P450 cDNA, encoding a new form of CYP3A protein, was isolated from a liver cDNA library of a male rat using anti-P4506β-1and anti-P4506β-2 antibodies and the CYP3A2 cDNA. The cDNA (CYP3A18 cDNA) consisted of 1987 nucleotides, in which were contained an open reading frame of 1491 bp (corresponding to 497 amino acids), 5′-(59bp) and 3′-noncoding regions (437 bp). The deduced amino acid sequence of CYP3A18 cDNA was completely identical in the first 27 N-terminal residues of P4506β-2 previously isolated by us (Nagata et al. J Biochem 1990: 107, 718-725) from livers of rats treated with dexamethasone, and also shared higher extents of similarity with hamster CYP3A10 (78.5%) than with rat CYP3As previously sequenced (66.3-69.3%). Northern blot analyses indicated a male-dominant expression of this new CYP3A mRNA and enhanced expression in dexamethasone-or pregnenolone-16α-carbonitrile (PCN)-treated, but not phenobarbital- or 3-methylcholanthrene-treated rats. Expressed CYP3A18 protein in COS-1 cells migrated at a position identical to that of purified P4506β-2 on sodium dodecyl sulfate-acrylamide gel electrophoresis and catalyzed 16β- and 6α-hydroxylations of testosterone. In contrast to CYP3A1 and CYP3A2, cytochrome b5 was not essential for maximal catalytic activities of recombinant CYP3A18 protein. These results, together with ontogenic profiles of CYP3A18 mRNA and P4506β-2 protein, indicate that the newly isolated CYP3A18 cDNA encodes P4506β-2 in rat liver.
KW - A male-dominant expression
KW - Cytochrome b
KW - Recombinant CYP3A
KW - Testosterone 16α-hydroxylation
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U2 - 10.1097/00008571-199602000-00009
DO - 10.1097/00008571-199602000-00009
M3 - Article
C2 - 8845857
AN - SCOPUS:0029993673
VL - 6
SP - 103
EP - 111
JO - Pharmacogenetics
JF - Pharmacogenetics
SN - 1744-6872
IS - 1
ER -