title: Subcellular localization of ATBF1 regulates MUC5AC transcription in gastric cancer.
abstract: Human gastric epithelium has a unique mucin gene expression pattern, which becomes markedly altered in gastrointestinal disorder. This alteration in mucin expression, including the mucin MUC5AC, may be related to the development and prognosis of gastric cancers, and MUC5AC-positive gastric cancer has been reported to be poor prognosis. However, the molecular mechanism of MUC5AC transcriptional regulation has not been fully elucidated. AT motif-binding factor 1 (ATBF1) is a homeotic transcriptional regulatory factor recently identified as a tumor suppressor gene, and its subcellular localization suggests a link to cell proliferation and differentiation. We investigated the mechanism of MUC5AC transcriptional regulation by ATBF1. In 123 gastric cancer lesions, ATBF1 expressed in the nucleus significantly suppressed MUC5AC expression, as determined by immunohistochemistry. In addition, analysis of the MUC5AC promoter region revealed an AT motif-like element. This element was found to be essential for ATBF1 suppression of MUC5AC promoter activity as shown in a dual luciferase-reporter assay. Over-expressed ATBF1 also significantly suppressed endogenous MUC5AC protein expression in gastric cancer cells. Chromatin immunoprecipitation demonstrated that ATBF1 binds to the AT motif-like element in the MUC5AC promoter. These results indicate that ATBF1 in the nucleus negatively regulates the MUC5AC gene in gastric cancer by binding to an AT motif-like element in the MUC5AC promoter.
authors.affiliation: Department of Internal Medicine and Bioregulation, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Mori
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kataoka
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Miura
authors.forename: Makoto
authors.initials: M
authors.lastname: Kawaguchi
authors.forename: Eiji
authors.initials: E
authors.lastname: Kubota
authors.forename: Naotaka
authors.initials: N
authors.lastname: Ogasawara
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Oshima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanida
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ohara
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Mizoshita
authors.forename: Masae
authors.initials: M
authors.lastname: Tatematsu
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Asai
authors.forename: Takashi
authors.initials: T
authors.lastname: Joh
mesh_terms: D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D005753:Gastric Mucosa / Q000737:chemistry / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D055271:Mucin 5AC; D009077:Mucins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D018398:Homeodomain Proteins; C524678:MUC5AC protein, human; D055271:Mucin 5AC; D009077:Mucins; D011993:Recombinant Fusion Proteins; C071660:ZFHX3 protein, human; D008156:Luciferases