title: The potential of the cruciform structure formation as an important factor influencing p53 sequence-specific binding to natural DNA targets.
abstract: p53 is one of the most important tumor suppressors which responds to DNA damage by binding to DNA and regulating the transcription of genes involved in cell cycle arrest, apoptosis, or senescence. As it was shown previously, p53 binding to DNA is strongly influenced by DNA topology. DNA supercoiling is fundamentally important for a wide range of biological processes including DNA transcription, replication, recombination, control of gene expression and genome organization. In this study, we investigated the cruciform structures formation of various inverted repeats in p53-responsive sequences from p21, RGC, mdm2 and GADD45 promoters under negative superhelical stress, and analyzed the effects of these DNA topology changes on p53-DNA binding. We demonstrated using three different methods (gel retardation analyses, ELISA and magnetic immunoprecipitation assay) that the p53 protein binds preferentially to negatively supercoiled plasmid DNAs with p53-responsive sequence presented as a cruciform structure. Not only the appearance of the cruciform structures within naked supercoiled DNA, but also the potential of the binding sites for adopting the non-B structures can contribute to a more favorable p53-DNA complex.
authors.affiliation: Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic.
authors.forename: Eva B
authors.initials: EB
authors.lastname: Jagelská
authors.forename: Hana
authors.initials: H
authors.lastname: Pivonková
authors.forename: Miroslav
authors.initials: M
authors.lastname: Fojta
authors.forename: Václav
authors.initials: V
authors.lastname: Brázda
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D055029:Inverted Repeat Sequences; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D000097642:GADD45 Proteins
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D004277:DNA, Single-Stranded; D004278:DNA, Superhelical; D047908:Intracellular Signaling Peptides and Proteins; D051736:Proto-Oncogene Proteins c-mdm2; D016159:Tumor Suppressor Protein p53; D000097642:GADD45 Proteins