title: Transrepression activity of T-box1 in a gene regulation network in mouse cells.
abstract: T-box1 (TBX1) has been identified as a candidate disease-causing gene in DiGeorge syndrome/conotruncal anomaly face syndrome (DGS/CAFS). Tbx1 can function as a transcriptional transactivator as well as a transrepressor. Although the transactivating role of Tbx1 has been the focus of a number of published studies, its transrepression activity has been largely unexplored. Thus, this study centers on the identification of potential transrepressed targets of Tbx1. By subtractive hybridization, we compared the expression profiles of control mouse P19 cells and P19 cells depleted of Tbx1 via RNA interference. We identified 127 genes that were potentially transrepressed by Tbx1. Of the transrepressed genes, we focused on Ywhae and C1qbp and carried out promoter assays. The results showed that Tbx1 potentially transrepresses the promoter activities of these genes via palindromic sequences, including 5'-CCACAG-3' and 5'-(C/G)TGTG(C/G)-3', harbored within the promoters. Electromobility shift assays also showed that Tbx1 specifically interacts with certain portions of these promoter sequences. Moreover, the construction of Tbx1 mutants containing known human TBX1 mutations showed that these mutations result in the loss of Tbx1 transrepression activity. These results indicate that Tbx1 functions as a transrepressor in a gene regulation network, wherein Ywhae and C1qbp are 2 of the targets transrepressed by Tbx1 via T-box binding elements. Hence, the loss of TBX1 transrepression activity could be associated with the disease phenotypes of patients with DGS/CAFS.
authors.affiliation: Institute for Integrated Medical Sciences, Tokyo Women's Medical University, Tokyo 162-8666, Japan.
authors.forename: Karen K L
authors.initials: KK
authors.lastname: Yee
authors.forename: Hisato
authors.initials: H
authors.lastname: Yagi
authors.forename: Rumiko
authors.initials: R
authors.lastname: Matsuoka
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Toru
authors.initials: T
authors.lastname: Furukawa
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics; D000818:Animals; D045744:Cell Line, Tumor; D018628:Gene Dosage; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics; D051379:Mice; D024101:Mitochondrial Proteins; D009154:Mutation; D034741:RNA, Small Interfering / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; C490193:C1qbp protein, mouse; D018960:Hyaluronan Receptors; D024101:Mitochondrial Proteins; D034741:RNA, Small Interfering; D020825:T-Box Domain Proteins; C108625:TBX1 protein, human; C491573:Tbx1 protein, mouse; C576823:Ywhae protein, mouse