Isolation and characterization of the human cytochrome P450 CYP1B1 gene.
Previously, we identified a novel human cytochrome P450 cDNA that is inducible by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and represents the first member of a new subfamily designated cytochrome P4501B1 (CYP1B1; Sutter, T. R., Tang, Y. M., Hayes, C. L., Wo, Y. P., Jabs, E. W., Li, X., Yin, H., Cody, C. W., and Greenlee, W. F. (1994) J. Biol. Chem. 269, 13092-13099). Here, we report on the isolation and initial characterization of the CYP1B1 gene. The CYP1B1 gene maps to human chromosome 2 at 2p21-22 and contains three exons and two introns. The putative open reading frame starts in the second exon and is 1629 base pairs in length. Southern analysis using DNA probes directed to each of the three exons confirmed that CYP1B1 is a single copy gene. Human CYP1B1 differs from its two most closely related members of the cytochrome P450 superfamily, CYP1A1 and CYP1A2, in the number of exons (3 versus 7) and chromosome location (2 versus 15). A single transcription initiation site was identified by primer extension analysis and S1 nuclease mapping. Based on nucleotide sequence analysis, the CYP1B1 gene lacks a consensus TATA box in the promoter region and contains nine TCDD-responsive enhancer core binding motifs (5'-GCGTG-3') located within a 2.5-kilobase pair genomic fragment 5'-ward of the transcription initiation start site. Deletion analysis of chloramphenicol acetyltransferase reporter gene constructs containing 5' CYP1B1 genomic fragments indicates that a region from -1022 to -835 containing three of the nine core binding motifs contributes to the TCDD-inducible expression of CYP1B1.
Tang
Y M
YM
Department of Pharmacology and Toxicology, Purdue University, West Lafayette, Indiana 47907, USA.
Wo
Y Y
YY
Stewart
J
J
Hawkins
A L
AL
Griffin
C A
CA
Sutter
T R
TR
Greenlee
W F
WF
D001189:Aryl Hydrocarbon Hydroxylases; D001483:Base Sequence; D015139:Blotting, Southern; D002874:Chromosome Mapping; D065633:Cytochrome P-450 CYP1B1; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D017930:Genes, Reporter; D006801:Humans; D008969:Molecular Sequence Data; D017384:Sequence Deletion; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism
D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D065633:Cytochrome P-450 CYP1B1; D015719:Single-Strand Specific DNA and RNA Endonucleases