title: Gli regulates MUC5AC transcription in human gastrointestinal cells.
abstract: MUC5AC is a well-known gastric differentiation marker, which has been frequently used for the classification of stomach cancer. Immunohistochemistry revealed that expression of MUC5AC decreases accompanied with increased malignant property of gastric mucosa, which further suggests the importance of MUC5AC gene regulation. Alignment of the 5'-flanking regions of MUC5AC gene of 13 mammal species denoted high homology within 200 bp upstream of the coding region. Luciferase activities of the deletion constructs containing upstream 451 bp or shorter fragments demonstrated that 15 bp region between -111 and -125 bp plays a critical role on MUC5AC promoter activity in gastrointestinal cells. We found a putative Gli-binding site in this 15 bp sequence, and named this region a highly conserved region containing a Gli-binding site (HCR-Gli). Overexpression of Gli homologs (Gli1, Gli2, and Gli3) clearly enhanced MUC5AC promoter activity. Exogenous modulation of Gli1 and Gli2 also affected the endogenous MUC5AC gene expression in gastrointestinal cells. Chromatin immunoprecipitation assays demonstrated that Gli1 directly binds to HCR-Gli: Gli regulates MUC5AC transcription via direct protein-DNA interaction. Conversely, in the 30 human cancer cell lines and various normal tissues, expression patterns of MUC5AC and Gli did not coincide wholly: MUC5AC showed cell line-specific or tissue-specific expression whereas Gli mostly revealed ubiquitous expression. Luciferase promoter assays suggested that the far distal MUC5AC promoter region containing upstream 4010 bp seems to have several enhancer elements for gene transcription. In addition, treatments with DNA demethylation reagent and/or histone deacetylase inhibitor induced MUC5AC expression in several cell lines that were deficient in MUC5AC expression. These results indicated that Gli is necessary but not sufficient for MUC5AC expression: namely, the multiple regulatory mechanisms should work in the distal promoter region of MUC5AC gene.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kageyama-Yahara
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Nobutake
authors.initials: N
authors.lastname: Yamamichi
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Chiemi
authors.initials: C
authors.lastname: Nakayama
authors.affiliation: 1st Department of Pathology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Shiogama
authors.affiliation: 1st Department of Pathology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Inada
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Konno-Shimizu
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Kodashima
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Fujishiro
authors.affiliation: 1st Department of Pathology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tsutsumi
authors.affiliation: Second Department of Internal Medicine, Wakayama Medical College, Kimiidera, Wakayama, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Ichinose
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D017124:Conserved Sequence; D005770:Gastrointestinal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D041981:Gastrointestinal Tract / Q000378:metabolism* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D055271:Mucin 5AC / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000071676:Zinc Finger Protein GLI1
chemical_list: C400551:GLI1 protein, human; C524678:MUC5AC protein, human; D055271:Mucin 5AC; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1