The Wwox knockdown enhances Tax-mediated cellular transformation. (A) Enhancement of Tax-mediated colony formation by Wwox knockdown. Rat-1 cells stably expressing Tax alone or together with different Wwox shRNA constructs were plated in soft agar for colony formation. Photographs were taken at day 21 after plating. Original magnification was ×100. (B) Summary of colony formation efficiency performed in panel A. These data represent mean (± SD), and values for P were obtained using Student t test. **P < .01. (C) Knockdown efficiency of Wwox by shRNAs. Semiquantitative RT-PCR analysis and IB assay were performed, respectively, to examine the RNA and protein expression levels of Wwox and TAX in the Rat-1 stable cell lines used in panel A. (D). Restoration of Tax-mediated transformation of p100^−/− MEFs by Wwox knockdown. p100^−/− MEFs stably expressing Tax alone or together with different Wwox shRNA constructs were subjected to soft agar colony formation and IB assays as described in panel A.