title: CPEB-mediated ZO-1 mRNA localization is required for epithelial tight-junction assembly and cell polarity.
abstract: CPEB is a translational regulatory sequence-specific RNA-binding protein that controls germ cell development. Here we show that CPEB heterozygous female mice are fertile but contain disorganized mammary epithelial cells, in which zonal occludens-1 and claudin-3, apical tight-junction proteins, are mislocalized. CPEB depletion from mammary epithelial cells disrupts zonal occludens-1 apical localization and tight-junction distribution; conversely, ectopic expression of CPEB enhances zonal occludens-1 localization. CPEB and zonal occludens-1 mRNA are co-localized apically and zonal occludens-1 3' untranslated region-binding sites for CPEB are necessary for RNA localization. In a three-dimensional culture system that models lumen-containing mammary ducts, depletion of CPEB or zonal occludens-1 impairs central cavity formation, indicating a loss of cell polarity. Cavity formation in zonal occludens-1-depleted cells is rescued when they are transduced with zonal occludens-1 mRNA containing, but not lacking, CPEB-binding sites. Our data demonstrate that CPEB-mediated zonal occludens-1 mRNA localization is essential for tight-junction assembly and mammary epithelial cell polarity.
authors.affiliation: Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Nagaoka
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Udagawa
authors.forename: Joel D
authors.initials: JD
authors.lastname: Richter
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001665:Binding Sites; D018938:Caco-2 Cells; D016764:Cell Polarity / Q000235:genetics; D062465:Claudin-3; D057167:Claudins / Q000378:metabolism; D004285:Dogs; D004848:Epithelium / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006579:Heterozygote; D006801:Humans; D008321:Mammary Glands, Animal; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009865:Oocytes / Q000166:cytology; D010750:Phosphoproteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D019108:Tight Junctions / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein; D039221:mRNA Cleavage and Polyadenylation Factors / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; C568122:CLDN3 protein, human; C490386:CPEB1 protein, human; D062465:Claudin-3; D057167:Claudins; C568123:Cldn3 protein, mouse; D008565:Membrane Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; D014157:Transcription Factors; D062826:Zonula Occludens-1 Protein; D039221:mRNA Cleavage and Polyadenylation Factors