title: Expression of divalent metal transporter 1 (DMT1) isoforms in first trimester human placenta and embryonic tissues.
abstract: BACKGROUND
  Divalent metal transporter 1 (DMT1) is a transmembrane glycoprotein which mediates the proton-coupled transport of a variety of divalent metal ions. Two isoforms, which differ by the presence (DMT1-IRE) or absence (DMT1-nonIRE) of an iron-responsive element (IRE) in their 3' untranslated region, are implicated in apical iron transport and endosomal iron transport respectively. Although the expression pattern of DMT1 isoforms is tissue specific in adult, data regarding its expression in embryonic tissues are lacking.
  
  
  METHODS
  Semiquantitative RT-PCR and immunohistochemistry were used to study the mRNA and protein expression of both DMT1 isoforms in embryonic tissues between 8 and 14 weeks gestational age.
  
  
  RESULTS
  DMT1-IRE and DMT1-nonIRE expressions were ubiquitous in embryonic tissues examined. In the lung, statistically significant correlations were found between the levels of DMT1 isoform expression and gestational age. In the placenta, DMT1-IRE was the predominantly expressed isoform. Both isoform proteins were localized in embryonic epithelial cellular membrane.
  
  
  CONCLUSIONS
  Both DMT1 isoforms are ubiquitously expressed in embryonic tissues in the first trimester. Predominant DMT1-IRE isoform expression in placenta suggests an iron-regulatory mechanism reminiscent of that in the adult duodenum. Epithelial distributions of both DMT1 isoforms are associated with the absorptive or excretory functions of the expressed tissues.
authors.affiliation: Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, People's Republic of China.
authors.forename: W S
authors.initials: WS
authors.lastname: Chong
authors.forename: P C
authors.initials: PC
authors.lastname: Kwan
authors.forename: L Y
authors.initials: LY
authors.lastname: Chan
authors.forename: P Y
authors.initials: PY
authors.lastname: Chiu
authors.forename: T K
authors.initials: TK
authors.lastname: Cheung
authors.forename: T K
authors.initials: TK
authors.lastname: Lau
mesh_terms: D000328:Adult; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000096:biosynthesis* / Q000737:chemistry*; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D007477:Ions; D033862:Iron-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry*; D007668:Kidney / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D010920:Placenta / Q000196:embryology* / Q000378:metabolism; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014018:Tissue Distribution; D000099236:Solute Carrier Family 11, Member 2
chemical_list: D027682:Cation Transport Proteins; D017931:DNA Primers; D007477:Ions; D033862:Iron-Binding Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D000099236:Solute Carrier Family 11, Member 2