title: Cold shock protein YB-1 is involved in hypoxia-dependent gene transcription.
abstract: Hypoxia-dependent gene regulation is largely orchestrated by hypoxia-inducible factors (HIFs), which associate with defined nucleotide sequences of hypoxia-responsive elements (HREs). Comparison of the regulatory HRE within the 3' enhancer of the human erythropoietin (EPO) gene with known binding motifs for cold shock protein Y-box (YB) protein-1 yielded strong similarities within the Y-box element and 3' adjacent sequences. DNA binding assays confirmed YB-1 binding to both, single- and double-stranded HRE templates. Under hypoxia, we observed nuclear shuttling of YB-1 and co-immunoprecipitation assays demonstrated that YB-1 and HIF-1α physically interact with each other. Cellular YB-1 depletion using siRNA significantly induced hypoxia-dependent EPO production at both, promoter and mRNA level. Vice versa, overexpressed YB-1 significantly reduced EPO-HRE-dependent gene transcription, whereas this effect was minor under normoxia. HIF-1α overexpression induced hypoxia-dependent gene transcription through the same element and accordingly, co-expression with YB-1 reduced HIF-1α-mediated EPO induction under hypoxic conditions. Taken together, we identified YB-1 as a novel binding factor for HREs that participates in fine-tuning of the hypoxia transcriptome.
authors.affiliation: Nephrology and Clinical Immunology, RWTH University of Aachen, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rauen
authors.affiliation: Nephrology and Clinical Immunology, RWTH University of Aachen, Aachen, Germany; Pneumology, University Medical Center, University of Freiburg, Freiburg, Germany.
authors.forename: Bjoern C
authors.initials: BC
authors.lastname: Frye
authors.affiliation: Nephrology and Clinical Immunology, RWTH University of Aachen, Aachen, Germany.
authors.forename: Jialin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Nephrology and Clinical Immunology, RWTH University of Aachen, Aachen, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Raffetseder
authors.affiliation: Nephrology and Clinical Immunology, RWTH University of Aachen, Aachen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Alidousty
authors.affiliation: Nephrology and Clinical Immunology, RWTH University of Aachen, Aachen, Germany.
authors.forename: Abdelaziz
authors.initials: A
authors.lastname: En-Nia
authors.affiliation: Nephrology and Clinical Immunology, RWTH University of Aachen, Aachen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Floege
authors.affiliation: Nephrology and Hypertension, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Mertens
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D015687:Cell Hypoxia / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D057773:Cold Shock Proteins and Peptides / Q000378:metabolism*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D021381:Protein Transport; D020218:Response Elements / Q000235:genetics; D020539:Sequence Analysis, Protein; D014158:Transcription, Genetic; D051840:Y-Box-Binding Protein 1 / Q000378:metabolism*
chemical_list: D057773:Cold Shock Proteins and Peptides; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051840:Y-Box-Binding Protein 1
keywords: Cold shock protein; Gene regulation; HRE; Hypoxia; YB-1