Regulation of tight junctions during the epithelium-mesenchyme transition: direct repression of the gene expression of claudins/occludin by Snail.
Snail is a transcription repressor that plays a central role in the epithelium-mesenchyme transition (EMT), by which epithelial cells lose their polarity. Claudins and occludin are integral membrane proteins localized at tight junctions, which are responsible for establishing and maintaining epithelial cell polarity. We examined the relationship between Snail and the promoter activity of claudins and occludin. When Snail was overexpressed in cultured mouse epithelial cells, EMT was induced with concomitant repression of the expression of claudins and occludin not only at the protein but also at the mRNA level. We then isolated the promoters of genes encoding claudins and occludin, in which multiple E-boxes were identified. Transfection experiments with various promoter constructs as well as electrophoretic mobility assays revealed that Snail binds directly to the E-boxes of the promoters of claudin/occludin genes, resulting in complete repression of their promoter activity. Because the gene encoding E-cadherin was also reported to be repressed by Snail, we concluded that EMT was associated with the simultaneous repression of the genes encoding E-cadherin and claudins/occludin (i.e. the expression of adherens and tight junction adhesion molecules, respectively).
Ikenouchi
Junichi
J
Department of Cell Biology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Matsuda
Miho
M
Furuse
Mikio
M
Tsukita
Shoichiro
S
D000818:Animals; D001483:Base Sequence; D019921:Biotinylation; D015152:Blotting, Northern; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D062445:Claudin-1; D057167:Claudins; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004848:Epithelium / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D041681:NIH 3T3 Cells; D062793:Occludin; D009841:Oligonucleotides / Q000737:chemistry; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D000071250:Snail Family Transcription Factors; D019108:Tight Junctions / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
C568108:CLDN1 protein, human; C491875:CLDN2 protein, human; D015820:Cadherins; D062445:Claudin-1; D057167:Claudins; C568113:Cldn1 protein, mouse; C113371:Cldn2 protein, mouse; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; C568986:Ocln protein, mouse; D009841:Oligonucleotides; D012333:RNA, Messenger; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors