title: Estrogen-specific sulfotransferase (SULT1E1) in bovine placentomes: inverse levels of mRNA and protein in uninucleated trophoblast cells and trophoblast giant cells.
abstract: The bovine trophoblast produces significant amounts of estrogens. In maternal and fetal blood, estrogens occur predominantly in sulfonated forms, which are unable to bind to estrogen receptors (ESRs). However, estrogens may act as local factors in ESR-positive trophoblast cells or in the adjacent caruncular epithelium, which in addition to ESR highly expresses steroid sulfatase. Estrogen sulfonation is catalyzed by the cytosolic enzyme SULT1E1. Previous studies clearly indicated the trophoblast as the primary site of estrogen sulfonation. However, investigations into the cellular localization of SULT1E1 yielded conflicting results. In situ hybridization studies detected SULT1E1 mRNA only in trophoblast giant cells (TGCs), whereas in immunohistochemical experiments the SULT1E1 protein was virtually restricted to uninucleated trophoblast cells (UTCs). The aim of this work was to resolve this conflict by analyzing SULT1E1 expression in isolated UTCs and TGCs. Highly enriched pools of UTCs and TGCs were obtained from four bovine placentas (Days 118-130 of gestation) using an optimized fluorescence-activated cell sorting procedure. UTC and TGC pools were analyzed by quantitative RT-PCR and Western blot experiments to measure the amounts of SULT1E1 transcript and protein, respectively. In contrast to previously published results, both SULT1E1 transcript and SULT1E1 protein were clearly present in the UTC and TGC pools. However, some evidence indicated a higher transcript concentration in TGCs and a higher amount of protein in UTCs. Thus, our results resolve the conflicting results on the localization of SULT1E1 from earlier studies and suggest that posttranscriptional mechanisms play an important role in the control of SULT1E1 expression during TGC differentiation.
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Polei
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Viergutz
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Tomek
authors.affiliation: Clinic for Obstetrics, Gynecology and Andrology of Large and Small Animals, Faculty of Veterinary Medicine, Justus-Liebig-University, Giessen, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schuler
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany fuerbass@fbn-dummerstorf.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Fürbass
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism*; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D015238:Sulfotransferases
keywords: SULT1E1 mRNA; SULT1E1 protein; Western blot; estrogen sulfate; fluorescence-activated cell sorting (FACS); quantitative PCR