title: Temporal regulation of the expression of syncytin (HERV-W), maternally imprinted PEG10, and SGCE in human placenta.
abstract: Maternally imprinted PEG10 and SGCE, separated by approximately 2.15 Mb from Syncytin (HERV-W) gene at 7q21.3, are implicated in choriocarcinoma and Silver-Russell syndrome. Here we have analyzed the temporal regulation of mRNA expression of these genes in placenta and demonstrate that Syncytin gene activation is highest in term placenta, PEG10, downregulated at early hypoxic phase, and highly activated at 11-12 wk of gestation. In contrast, transcription from SGCE remained unchanged throughout pregnancy, suggesting two neighboring imprinted genes are differentially regulated at very early pregnancy. Additionally, accumulation of two major species of mRNA (8 kb and 3.1 kb) encoded by HERV-W in placenta is regulated: 3.1 kb mRNA level remained unchanged throughout pregnancy, whereas the production of 8 kb species was highest in term placenta. Western blot and immunohistochemical staining of placental tissues with monoclonal antibodies revealed a marked reduction of syncytin glycoprotein synthesis in late pregnancy. Therefore, the relative levels of 3.1 kb and 8 kb mRNAs in trophoblasts could regulate syncytin protein synthesis, possibly by competition of the two mRNA species for translational apparatus.
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London SE5 9RS, United Kingdom.
authors.forename: Alan
authors.initials: A
authors.lastname: Smallwood
authors.forename: Aris
authors.initials: A
authors.lastname: Papageorghiou
authors.forename: Kypros
authors.initials: K
authors.lastname: Nicolaides
authors.forename: M K R
authors.initials: MK
authors.lastname: Alley
authors.forename: Alice
authors.initials: A
authors.lastname: Jim
authors.forename: Geeta
authors.initials: G
authors.lastname: Nargund
authors.forename: Kamal
authors.initials: K
authors.lastname: Ojha
authors.forename: Stuart
authors.initials: S
authors.lastname: Campbell
authors.forename: Subhasis
authors.initials: S
authors.lastname: Banerjee
mesh_terms: D051017:Apoptosis Regulatory Proteins; D001483:Base Sequence; D003598:Cytoskeletal Proteins / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015686:Gene Products, env / Q000235:genetics* / Q000378:metabolism; D018392:Genomic Imprinting; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D010920:Placenta / Q000378:metabolism*; D010929:Placentation; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D049031:Sarcoglycans; D015533:Transcriptional Activation; D014327:Trophoblasts / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D015686:Gene Products, env; D008562:Membrane Glycoproteins; C432965:PEG10 protein, human; D011257:Pregnancy Proteins; D011506:Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D049031:Sarcoglycans; C405335:syncytin