Hepatocyte nuclear factor (HNF)-4alpha triggers formation of functional tight junctions and establishment of polarized epithelial morphology in F9 embryonal carcinoma cells.
F9 murine embryonal carcinoma cells provide an attractive system for facilitating molecular mechanisms for epithelial morphogenesis, since they have the capability of differentiating into polarized epithelial cells bearing an apical junctional complexes. We previously showed that a specific retinoid X receptor-retinoic acid receptor heterodimer transduced retinoid signals for biogenesis of functional tight junctions in F9 cells (Exp. Cell Res. 263, (2001) 163). In the present study we generated F9 cells expressing doxycycline-inducible hepatocyte nuclear factor (HNF)-4alpha, a nuclear receptor. We herein show that induction of HNF-4alpha initiates differentiation of F9 cells to polarized epithelial cells, in which tight-junction proteins occludin, claudin-6, claudin-7, and ZO-1 are concentrated at the apical-most regions of lateral membranes. Expression of occludin, claudin-6, and claudin-7 was induced in the cells by doxycycline treatment in a dose- and time-dependent manner, in terms of the amount of HNF-4alpha. In contrast, expression levels of ZO-1, ZO-2, E-cadherin, and beta-catenin were not altered by HNF-4alpha. We also demonstrate, by analysis of diffusion of labeled sphingomyelin, that the fence function of tight junctions is achieved by induction of HNF-4alpha. These findings indicate that HNF-4alpha triggers de novo formation of functional tight junctions and establishment of epithelial cell polarity.
Chiba
Hideki
H
Department of Pathology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan. hidchiba@sapmed.ac.jp
Gotoh
Tomoko
T
Kojima
Takashi
T
Satohisa
Seiro
S
Kikuchi
Keisuke
K
Osanai
Makoto
M
Sawada
Norimasa
N
D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D002454:Cell Differentiation / Q000235:genetics*; D016764:Cell Polarity / Q000235:genetics*; D048429:Cell Size / Q000235:genetics; D057167:Claudins; D004268:DNA-Binding Proteins; D004318:Doxycycline; D054278:Embryonal Carcinoma Stem Cells; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology* / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D051557:Hepatocyte Nuclear Factor 4; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D014411:Neoplastic Stem Cells; D062793:Occludin; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D019108:Tight Junctions / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C473255:CLDN7 protein, human; D057167:Claudins; D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; C568986:Ocln protein, mouse; D010750:Phosphoproteins; C501970:Tcfl4 protein, mouse; D014157:Transcription Factors; C122101:claudin 6; D004318:Doxycycline