FIG. 8.

NXF1-2xUBA sustains growth of cells depleted of endogenous NXF1 or p15. (A and B) SL2 cells stably transfected with plasmids expressing GFP or GFP-NXF1-2xUBA were transfected with NXF1 or p15 dsRNAs as indicated. Cell numbers were determined every second day for 8 days and every week for 6 weeks. In the GFP cell line, no cells survived NXF1 depletion. The surviving cells detected 31 days following p15 depletion died progressively after a few days. Cells expressing NXF1-2xUBA survived NXF1 or p15 depletion and started to grow exponentially 1 month after transfection of the dsRNAs.