Xenobiotic microsomal epoxide hydrolase: 5′ sequence of the human gene

Abstract

A cDNA for human microsomal epoxide hydrolase (mEH) was used to isolate genomic clones representing the 5′ portion of the corresponding human gene. A total of 1034 bases of mEH gene sequence were obtained that included exon 1 and 5′ flanking information. In contrast to the structure reported for the rat mEH gene (Falany et al. (1987) J. Biol. Chem. 262, 5924–5930), the human mEH gene lacked at CAAT ☐, but did contain a high-affinity CTF binding site at position −278 and an SV40 core enhancer element at position −525. TATA ☐es were identified at positions −32 and −29 for the human and rat genes, respectively. Sequence comparisons between 5′ flanking regions of the human and rat mEH genes demonstrated 47% homology, considerably less than the 83% conservation observed in the cDNA coding areas. Primer extension experiments localized the transcription initiation site of the human gene to a position 116 bases 5′ from the analogous site in the rat mEH gene.