Cdx2 and the Brm-type SWI/SNF complex cooperatively regulate villin expression in gastrointestinal cells.
In our recent study showing a correlation between Brm-deficiency and undifferentiated status of gastric cancer, we found that the Brm-type SWI/SNF complex is required for villin expression. To elucidate intestinal villin regulation more precisely, we here analyzed structure and function of the promoter of human villin. About 1.1 kb upstream of the determined major transcription start site, we identified a highly conserved region (HCR-Cdx) among mammals, which contains two binding sites for Cdx. Expression analyses of 30 human gastrointestinal cell lines suggested that villin is regulated by Cdx2. Introduction of Cdx family genes into colorectal SW480 cells revealed that villin is strongly induced strongly by Cdx2, moderately by Cdx1, and marginally by Cdx4. Knockdown of Cdx2 in SW480 cells caused a clear downregulation of villin, and reporter assays showed that HCR-Cdx is crucial for Cdx2-dependent and Brm-dependent villin expression. Immunohistochemical analyses of gastric intestinal metaplasia and cancer revealed that villin and Cdx2 expression are tightly coupled. GST pull-down assays demonstrated a direct interaction between Cdx2 and several SWI/SNF subunits. Chromatin immunoprecipitation analyses showed the recruitment of Cdx2 and Brm around HCR-Cdx. From these results, we concluded that Cdx2 regulates intestinal villin expression through recruiting Brm-type SWI/SNF complex to the villin promoter.
Yamamichi
Nobutake
N
Department of Microbiology and Immunology, Division of Host-Parasite Interaction, Institute of Medical Science, University of Tokyo, Shirokanedai Minato-ku, Tokyo Japan.
Inada
Ken-ichi
K
Furukawa
Chihiro
C
Sakurai
Kouhei
K
Tando
Toshio
T
Ishizaka
Aya
A
Haraguchi
Takeshi
T
Mizutani
Taketoshi
T
Fujishiro
Mitsuhiro
M
Shimomura
Ryoichi
R
Oka
Masashi
M
Ichinose
Masao
M
Tsutsumi
Yutaka
Y
Omata
Masao
M
Iba
Hideo
H
D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D000071616:CDX2 Transcription Factor; D045744:Cell Line, Tumor; D042002:Chromatin Assembly and Disassembly; D017124:Conserved Sequence; D041981:Gastrointestinal Tract / Q000166:cytology* / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008840:Microfilament Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D024363:Transcription Initiation Site
D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D018398:Homeodomain Proteins; D008840:Microfilament Proteins; D021122:Protein Subunits; C084011:SMARCA2 protein, human; D014157:Transcription Factors; C026615:villin