FIG 4.

siRNA knockdown of HD-PTP and its consequences for accumulation of SMN puncta in nuclei. HeLa cells were transfected with control siRNA (Ctrl) or a mixture of two HD-PTP siRNAs, and the transfections were repeated 24 h and 48 h later. Cells were then collected for immunostaining or Western blotting. (A) Fields of cells fixed, stained with DAPI, and immunostained for SMN. (Bottom row) SMN immunostaining alone. The white arrowhead indicates a nuclear SMN punctum. (Top row) Merge of SMN and DAPI channels. (B) Western blot showing levels of HD-PTP or control GAPDH protein in the cells at the time of their recovery. (C) SMN puncta in nuclei were counted and plotted as the mean number of puncta seen per 150 cells (left graph) and the mean number of punctum-free nuclei per 150 cells (right graph). The plotted values are means and standard deviations from the mean for 3 independent experiments, with 150 cells scored per experiment ****, P < 0.0001.