Identification of nucleolin as a

<p>γ<b>-H2AX-interacting protein.</b> (A) phospho-mimic GST-H2AX (H2AXS139E) pulls down several proteins including nucleolin from the nuclear extract of irradiated HeLa cells. Proteins were visualized by silver staining. (B) Pull-downed proteins from the nuclear extract of irradiated or un-irradiated HeLa cells were visualized by Western blot. Nucleolin was precipitated by both H2AX and H2AX (S139E), but NBS1 was precipitated by H2AX (S139E) from irradiated extract only. (C and D) Nucleolin interacts with γ-H2AX. Extracts from normal lymphoblastoid cells were immunoprecipitated with anti-nucleolin antibody (C), anti-γ-H2AX antibody (D) or normal rabbit IgG, and then the immuno-complexes were detected by Western blot analysis using indicated antibodies.