Use of molecular probes to study regulation of aromatase cytochrome P-450

• Published in: Biology of reproduction Vol. 42; no. 1; pp. 1 - 10
• Main Authors: MENDELSON, C. R, MEANS, G. D, MAHENDROO, M. S, CORBIN, C. J, STEINKAMPF, M. P, GRAHAM-LORENCE, S, SIMPSON, E. R
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01-01-1990
• Subjects: Adipose Tissue - analysis; Adipose Tissue - cytology; Adipose Tissue - enzymology; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Aromatase - analysis; Aromatase - genetics; Aromatase - metabolism; Biological and medical sciences; Cells, Cultured; DNA - analysis; DNA Probes; Enzymes and enzyme inhibitors; Female; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic - physiology; Granulosa Cells - analysis; Granulosa Cells - enzymology; Humans; Molecular Sequence Data; Oxidoreductases; RNA - analysis; Substrate Specificity; Human; Regulation(control); Enzymatic activity; Multienzyme complex; Complementary DNA; Enzyme; Cytochrome P450; Primary structure; Oestrogen synthase; Molecular probe; Gene expression; Mechanism of action
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod42.1.1

Aromatase, an enzyme complex localized in the endoplasmic reticulum of estrogen-producing cells, is composed of NADPH-cytochrome
P-450 reductase, and aromatase cytochrome P-450 (cytochrome P-450AROM). To define the molecular mechanisms involved in the
multifactorial regulation of cytochrome P-450AROM in estrogen-producing cells, we have isolated a cDNA specific for human
cytochrome P-450AROM and have used this cDNA to isolate the human cytochrome P-450AROM gene. The cDNA sequence encodes a polypeptide
of 503 amino acids and contains--near the carboxy-terminus, a region of high homology with the putative heme-binding regions
of other P-450 cytochromes. COS1 cells transfected with an expression plasmid containing the cytochrome P-450AROM cDNA had
the capacity to aromatize testosterone, androstenedione and 16 alpha-hydroxyandrostenedione, suggesting that a single polypeptide
catalyzes all steps of the aromatization reaction using either of the three major C19-substrates. The human cytochrome P-450AROM
gene is greater than 52 kb in size and consists of 10 exons and 9 introns. Hormonally induced changes in aromatase activity
of human ovarian granulosa and adipose stromal cells are associated with comparable changes in cytochrome P-450AROM gene expression
and synthesis, whereas the reductase component is only modestly affected. Studies are in progress to define the molecular
mechanisms involved in the regulation of cytochrome P-450AROM gene expression in estrogen-producing cells.