title: Runx3 expression in gastrointestinal tract epithelium: resolving the controversy.
abstract: We reported earlier that RUNX3 is expressed in human and mouse gastrointestinal tract (GIT) epithelium and that it functions as a tumor suppressor in gastric and colorectal tissues. However, there have been conflicting reports describing the absence of Runx3 in GIT epithelial cells. A part of the controversy may be derived from the use of a specific antibody by other groups (referred to as G-poly). Here, we show further evidence to support our earlier observations and provide a possible explanation for this apparent controversy. We generated multiple anti-RUNX3 monoclonal antibodies and found that RUNX3 antibodies recognizing the RUNX3 N-terminal region (residues 1-234) react with RUNX3 in gastric epithelial cells, whereas those recognizing the C-terminal region (beyond residue 234) did not. G-poly primarily recognizes the region beyond 234 and hence, is unable to detect Runx3 in this tissue.
authors.affiliation: Institute of Molecular and Cell Biology, Proteos, Singapore.
authors.forename: K
authors.initials: K
authors.lastname: Ito
authors.forename: K-i
authors.initials: KI
authors.lastname: Inoue
authors.forename: S-C
authors.initials: SC
authors.lastname: Bae
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
mesh_terms: D000818:Animals; D050677:Core Binding Factor Alpha 3 Subunit / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D005753:Gastric Mucosa / Q000737:chemistry*; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000737:chemistry*; D051379:Mice; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D050677:Core Binding Factor Alpha 3 Subunit; C493730:Runx3 protein, mouse