Cloning of cDNA and genomic DNA for human cytochrome P‐45011β

Abstract

A full‐length cDNA clone encoding steroid 11β‐hydroxylase (P‐450_11β) has been isolated from a cDNA library derived from human adrenal tumor. The insert of the clone contains an open reading frame encoding a protein of 503 amino acid residues together with a 4 bp 5'‐untranslated region and a 576 bp 3'‐untranslated region to which a poly(A) tract is attached. The promoter region of the P‐450_11β gene has also been isolated from a genomic library derived from human pre‐B cells. It contains a TATA box, a putative cAMP‐responsive element, several repeated sequences and two sequence elements similar to the consensus sequence for binding of AP‐1. A transient expression assay in Y‐1 adrenal tumor cells demonstrates that the promoter activity is remarkably enhanced by treatment of the cells with cAMP. In addition, analysis using deletion mutants containing various lengths of the 5'‐flanking region of the gene suggests that several cis‐acting elements participate in transcriptional regulation of human P‐450_11β gene.