Characterization of the human lung CYP2F1 gene and identification of a novel lung-specific binding motif.
The CYP2F1 gene encodes a cytochrome P450 enzyme capable of bioactivating a number of pulmonary-selective toxicants. The expression of CYP2F1 is highly tissue-selective; the highest expression is observed in the lung with little or no hepatic expression. The objective of these studies was to elucidate the mechanisms that govern the unique tissue-specific regulation of CYP2F1. Cosmid and bacterial artificial chromosome clones were screened and sequenced to identify a gene that spanned 14 kbp containing 10 exons, including an untranslated exon 1. Primer extension analysis and 5'-rapid amplification of cDNA ends were used to identify the transcription start site. Several sequences homologous to known cis-elements were identified in the 5'-upstream region of the CYP2F1 promoter. Transient transfection studies with luciferase reporter constructs demonstrated a significant functional lung cell-specific CYP2F1 promoter region (from position -129 to +115). DNase footprinting analysis of 1.6 kbp of the upstream sequence with nuclear extracts from human lung tissues revealed one strong DNA-protein complex at -152 to -182. This nuclear protein (called lung-specific factor, LSF) was present only in lung but not liver or heart tissues. Competitive electrophoretic mobility shift assays characterized a DNA consensus site, within the LSF-binding domain, that was highly similar to two E box motifs, but no known "E box" trans-factors were identified. These studies identified a novel LSF and its consensus sequence that may control tissue-specific expression of CYP2F1.
Carr
Brian A
BA
Department of Pharmacology and Toxicology, University of Utah, 30 S. 2000 E., Salt Lake City, UT 84112, USA.
Wan
Jie
J
Hines
Ronald N
RN
Yost
Garold S
GS
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics*; D000072467:Cytochrome P450 Family 2; D018076:DNA, Complementary / Q000737:chemistry; D005786:Gene Expression Regulation; D006801:Humans; D008168:Lung / Q000201:enzymology*; D008969:Molecular Sequence Data; D009928:Organ Specificity; D014158:Transcription, Genetic
D018076:DNA, Complementary; D003577:Cytochrome P-450 Enzyme System; C110332:CYP2F1 protein, human; D000072467:Cytochrome P450 Family 2