title: Tissue-specific promoters regulate aromatase cytochrome P450 expression.
abstract: In the human, estrogen biosynthesis occurs in several tissue sites, including ovary, placenta, adipose, and brain. Recent work from our laboratory has indicated that tissue-specific expression of aromatase cytochrome P450 (P450arom), the enzyme responsible for estrogen biosynthesis, is determined, in part, by the use of tissue-specific promoters. Thus the expression of P450arom in human ovary appears to utilize a promoter proximal to the translation start-site. This promoter is not utilized in placenta but instead, the promoter used to drive aromatase expression in placenta is at least 40 kb upstream from the translational start-site. In addition, there is a minor promoter used in the expression of a small proportion of placental transcripts which is 9 kb upstream from the start of translation. Transcripts from these promoters are also expressed in other fetal tissues including placenta-related cells such as JEG-3 choriocarcinoma cells, hydatidiform moles, and other fetal tissues such as fetal liver. On the other hand, in adipose tissue expression of P450arom may be achieved by yet another, adipose-specific promoter. The various 5'-untranslated exons unique for expression driven by each of these promoters are spliced into a common intron/exon boundary upstream from the translational start-site. This means that the protein expressed in each of the various tissue-specific sites of estrogen biosynthesis is identical.
authors: Cecil H. and Ida Green Center for Reproductive Biology Sciences, Department of Obstetrics/Gynecology, University of Texas Southwestern Medical Center, Dallas 75235-9051.
authors: E R
authors: ER
authors: Simpson
authors: M S
authors: MS
authors: Mahendroo
authors: G D
authors: GD
authors: Means
authors: M W
authors: MW
authors: Kilgore
authors: C J
authors: CJ
authors: Corbin
authors: C R
authors: CR
authors: Mendelson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001141:Aromatase / Q000235:genetics*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008969:Molecular Sequence Data; D010053:Ovary / Q000201:enzymology; D010920:Placenta / Q000201:enzymology; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D017386:Sequence Homology, Amino Acid
chemical_list: D001141:Aromatase