Figure 6. Both full-length and truncated YB-1 proteins interact with damaged DNA and DNA repair protein complexes. (A and B) Binding of YB-1 (WT) and YB-1 (1–219) with nonspecific [³²P]-labeled 660-nt dsDNA, control or modified with doxorubicin, as indicated (A), or 23-nt perfect or mismatched DNA duplexes (B), was examined by EMSA. (C) NIH3T3 cells were transiently transfected with plasmids encoding SFB-tagged YB-1 (1–219) and 24 h later were treated with 5 µM doxorubicin or 100 µM etoposide for 14 h. Whole-cell extracts were used for IP with streptavidin conjugated beads, and immunoprecipitated proteins were examined by WB. (D) NIH3T3 cells transiently expressing HA-tagged YB-1 (1–219) for 24 h were treated with 100 µM etoposide for 14 h and analyzed by IF using the indicated antibodies. Note that in response to treatment, truncated YB-1 was localized to the nuclear speckles, together with other DNA repair proteins, such as γН2А.Х and Mre11.