title: Involvement of transcription factor Ets-1 in the expression of the α3 integrin subunit gene.
abstract: The α3β1 integrin is an adhesion receptor for extracellular matrix proteins, and plays crucial roles in cell motility, proliferation, and differentiation. The aberrant expression of this adhesion molecule on tumor cells is frequently associated with their malignant behaviors. We previously reported that the Ets transcription factor-binding consensus sequence 133 bp upstream of the mouse α3 integrin gene is an important element for its expression in various tumor cell lines. In the present study, we attempted to identify a transcription factor bound to the Ets-consensus sequence, and found that Ets-1 bound to this sequence in an electrophoretic mobility shift assay, chromatin immunoprecipitation assay, and pull-down assay with a tandem repeat of the sequence as adsorbent. We next examined the role of Ets-1 in α3 integrin gene expression by use of a luciferase assay with a reporter plasmid containing the 5'-flanking region of the α3 integrin gene. Cotransfection of HEK293T cells with an Ets-1 expression construct and the reporter plasmid increased luciferase activity. By contrast, transfection of HT1080 cells (high α3 integrin expresser) with a dominant-negative mutant of Ets-1 decreased luciferase activity. Overexpression of Ets-1 in HepG2 hepatocellular carcinoma cells (low α3 integrin expresser) upregulated α3 integrin expression as assessed by immunoprecipitation. Finally, the induction of α3 integrin gene expression in HepG2 cells after transforming growth factor-β1 treatment was abrogated by the dominant-negative mutant of Ets-1. These results suggest that Ets-1 is involved in transcriptional activation of the α3 integrin gene through its binding to the Ets-consensus sequence at -133 bp.
authors.affiliation: Department of Microbiology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo 142-8501, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Kamoshida
authors.forename: Ayaka
authors.initials: A
authors.lastname: Matsuda
authors.forename: Kouji
authors.initials: K
authors.lastname: Katabami
authors.forename: Takumi
authors.initials: T
authors.lastname: Kato
authors.forename: Hiromi
authors.initials: H
authors.lastname: Mizuno
authors.forename: Wakana
authors.initials: W
authors.lastname: Sekine
authors.forename: Teruaki
authors.initials: T
authors.lastname: Oku
authors.forename: Saotomo
authors.initials: S
authors.lastname: Itoh
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsuiji
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Hattori
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Maitani
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tsuji
mesh_terms: D045744:Cell Line, Tumor; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D039422:Integrin alpha3 / Q000235:genetics*; D050784:Proto-Oncogene Protein c-ets-1 / Q000502:physiology*; D015533:Transcriptional Activation / Q000502:physiology; D053773:Transforming Growth Factor beta1 / Q000502:physiology; D015854:Up-Regulation
chemical_list: D039422:Integrin alpha3; D050784:Proto-Oncogene Protein c-ets-1; D053773:Transforming Growth Factor beta1