The human microsomal epoxide hydrolase gene (EPHX1): Complete nucleotide sequence and structural characterization

Journal Article · Thu Sep 15 04:00:00 EDT 1994 · Genomics

DOI:https://doi.org/10.1006/geno.1994.1520· OSTI ID:255144

Hassett, C; Robinson, K B; Beck, N B; Omiecinski, C J ^[1]

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1. Univ. of Washington, Seattle, WA (United States)

Human microsomal epoxide hydrolase (mEH) is a xenobiotic-metabolizing enzyme that detoxifies reactive epoxides to more water soluble dihyrodiol compounds. The authors have isolated and sequenced clones that encode the entire human mEH gene (EPHX1). The primary nuclear transcript, extending from the start of transcription to the site of poly(A) addition, is 20,271 nucleotides in length. The human mEH gene contains 9 exons, separated by 8 introns; canonical intron/exon boundary sites are observed at each junction. The introns vary in size from 335 to 6696 bp and contain numerous repetitive DNA elements, including 18 Alu sequences (each > 100 nucleotides in length) within 4 introns. Alu sequences were classified with respect to subfamily assignment. Two thousand eighteen nucleotides 5` of the transcription start and 2501 nucleotides 3` of the poly(A) addition sites were also sequenced. To evaluate the human mEH promoter, chimeric constructs were prepared linking portions of the 5` mEH flanking sequence (up to -693 bp) to a CAT reporter gene, followed by transient transfection in both COS-1 and HepG2 cells. Results from these expression experiments suggest that the human mEH gene contains a weak core promoter and that inclusion of DNA sequences 5` of the minimal promoter region negatively regulates constitutive transcription. 50 refs., 6 figs., 2 tabs.

• OSTI ID: 255144
• Journal Information: Genomics, Journal Name: Genomics Journal Issue: 2 Vol. 23; ISSN 0888-7543; ISSN GNMCEP
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
DNA SEQUENCING
ENZYMATIC HYDROLYSIS
EPOXIDES
GENES
HYDROLASES