Y box-binding protein-1 binds preferentially to single-stranded nucleic acids and exhibits 3'-->5' exonuclease activity

• Published in: Nucleic acids research Vol. 29; no. 5; pp. 1200 - 1207
• Main Authors: Izumi, H, Imamura, T, Nagatani, G, Ise, T, Murakami, T, Uramoto, H, Torigoe, T, Ishiguchi, H, Yoshida, Y, Nomoto, M, Okamoto, T, Uchiumi, T, Kuwano, M, Funa, K, Kohno, K
• Format: Journal Article
• Language: English
• Published: England Oxford Publishing Limited (England) 01-03-2001; Oxford University Press
• Subjects: Binding; Binding Sites; Binding, Competitive; CCAAT-Enhancer-Binding Proteins; CCAAT-Enhancer-Binding Proteins - chemistry; CCAAT-Enhancer-Binding Proteins - genetics; CCAAT-Enhancer-Binding Proteins - metabolism; Cell and Molecular Biology; Cell- och molekylärbiologi; chemistry; Cisplatin; Cisplatin - pharmacology; Competitive; Cultured; Dimerization; DNA; DNA - metabolism; DNA, Single-Stranded - metabolism; DNA-Binding Proteins; drug effects; Exonucleases; Exonucleases - metabolism; genetics; Glutathione Transferase; Glutathione Transferase - genetics; Glutathione Transferase - metabolism; Humans; metabolism; Mutation; NFI Transcription Factors; Nuclear Proteins; Oligonucleotides; Oligonucleotides - metabolism; pharmacology; Protein Binding; Protein Binding - drug effects; Protein Biosynthesis; Recombinant Fusion Proteins; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; RNA-Binding Proteins; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Single-Stranded; Transcription Factors; Tumor Cells; Tumor Cells, Cultured; Y-Box-Binding Protein 1
• ISSN: 1362-4962; 0305-1048; 1362-4962
• DOI: 10.1093/nar/29.5.1200

We have previously shown that Y box-binding protein-1 (YB-1) binds preferentially to cisplatin-modified Y box sequences. Based on structural and biochemical data, we predicted that this protein binds single-stranded nucleic acids. In the present study we confirmed the prediction and also discovered some unexpected functional features of YB-1. We found that the cold shock domain of the protein is necessary but not sufficient for double-stranded DNA binding while the C-tail domain interacts with both single-stranded DNA and RNA independently of the cold shock domain. In an in vitro translation system the C-tail domain of the protein inhibited translation but the cold shock domain did not. Both in vitro pull-down and in vivo co-immunoprecipitation assays revealed that YB-1 can form a homodimer. Deletion analysis mapped the C-tail domain of the protein as the region of homodimerization. We also characterized an intrinsic 3'-->5' DNA exonuclease activity of the protein. The region between residues 51 and 205 of its 324-amino acid extent is required for full exonuclease activity. Our findings suggest that YB-1 functions in regulating DNA/RNA transactions and that these actions involve different domains.