Temporal analysis of arsenite-stressed HeLa cells reveals P bodies increase in size and number before formation of stress granules. (A) HeLa cells were fixed at several time points after arsenite stress, from 0 (no arsenite added) to 60 min. Endogenous Pabp (red) and Rck (green) were used as stress granule and P-body markers, respectively. DAPI staining (blue) reveals the nucleus. Images are typical of three independent experiments. (B) Representative images of HeLa cells after 45 and 60 min of arsenite stress, demonstrating a greater accumulation of Rck in stress granules at 60 min.