Fig. 6

Live-cell imaging of RBM45 nuclear stress body (NSB) and nuclear inclusion formation during conditions of cellular stress. HEK293 cells induced to express N-terminal GFP-tagged RBM45 were used to visualize the subcellular distribution of RBM45 during normal conditions and during acute and chronic cellular stress. a In untreated cells, RBM45 is predominantly nuclear and diffusely localized throughout the nucleus. b Treatment with 0.5 mM sodium arsenite for 1 h causes the formation of numerous RBM45-positive nuclear stress bodies (NSBs; arrowheads). Cells were treated with 0.5 mM sodium arsenite at t = 0 h. Under conditions of acute cellular stress, NSB formation is reversible, most RBM45-positive NSBs have dissipated by t = 6 h, and RBM45 remains diffusely localized throughout the nucleus for the remainder of the experiment. c Chronic cellular stress leads to the entrapment of RBM45 in nuclear inclusions. Cells were treated with 0.1 mM sodium arsenite for 12 h to assess the effect of chronic cellular stress on RBM45 subcellular distribution. Because of the lower concentration of sodium arsenite, the time course of NSB formation is altered. Following removal of sodium arsenite (panel “Washout”), RBM45 remains in nuclear inclusions for the remaining 12 h duration of the experiment (arrowheads). For all panels, scale bar = 5 μm