title: Low pH enhances Sp1 DNA binding activity and interaction with TBP.
abstract: Sp1 is involved in the regulation of a wide variety of genes, including housekeeping genes and genes involved in tumor growth. Sp1 is a member of the C2-H2 zinc-finger family and is important for protection against cellular acidosis in cells that grow under hypoxic or acidic conditions, such as tumor cells. To obtain an insight into the molecular mechanisms underlying pH-dependent transcription by Sp1, both its DNA binding activity and its interaction with TATA binding protein (TBP) were investigated under various pH conditions. We show here that the DNA binding activity of Sp1 increased and Sp1 formed a stable interaction with TBP at low pH. These findings indicate that pH changes significantly modulate the activity of Sp1 and thus contribute to the cellular response under hypoxic or acidic conditions.
authors.affiliation: Department of Molecular Biology, University of Occupational and Environmental Health, School of Medicine, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Torigoe
authors.forename: Hiroto
authors.initials: H
authors.lastname: Izumi
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishiguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Okamoto
authors.forename: Hideaki
authors.initials: H
authors.lastname: Itoh
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Kohno
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D019175:DNA Methylation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011485:Protein Binding; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D035181:TATA-Box Binding Protein / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D015032:Zinc / Q000494:pharmacology
chemical_list: D016329:Sp1 Transcription Factor; D035181:TATA-Box Binding Protein; D004247:DNA; D015032:Zinc