Figure 2

Expression of TDP-43 and TDP-43^A315T induce p53-dependent apoptosis of neural progenitors. (a) Scheme of human TDP-43 and TDP-43^A315T with a single point mutation in the glycine-rich C-terminal region, nuclear localization signal (NLS), nuclear export signal (NES), RNA recognition motif (RRM). (b) Transfection of neural progenitors results in a 2.4-fold expression of TDP-43 and 2.8-fold for TDP-43^A315T compared to endogenous levels. Expression of Cdkn1 reduces endogenous TDP-43 levels suggesting a reciprocal interaction with TDP-43. (c) Expression of TDP-43 and TDP-43^A315T activates caspase-3 (arrows) and drives cells in the ventricular zone into apoptosis within 24 hours. (d) TDP-43 and TDP-43^A315T expression induce caspase-3 activity and apoptosis in transfected cells (GFP⁺). Values are shown as the proportion of transfected cells (GFP⁺). (e) TDP-43 and TDP-43^A315T expression reduce the proportion of Pax6⁺GFP⁺ progenitors compared to control transfected cells (Ctrl.). Values are shown as the proportion of transfected cells (GFP⁺). (f,g) TDP-43 expression causes mislocalization of GFP⁺pH3⁺ cells away from the ventricular lining (GFP control: arrows) to more basal locations (TDP-43: arrowheads) and reduces the proportion of ventricular progenitors in M-phase (pH3⁺) compared to control transfected cells (Ctrl.). Values are shown as the proportion of transfected cells (GFP⁺). (h) TDP-43 and TDP-43^A315T expression reduce differentiation to Tbr2⁺ basal progenitors compared to control transfected cells (Ctrl.). Values are shown as the proportion of transfected cells (GFP⁺). (i) TDP-43 overexpressing progenitors fail to generate Tbr1⁺ neurons in the cortical plate. Scale bar in c and f = 25 µm. Dashed line marks the telencephalic vesicle lining. tTest ^*P < 0.05, ^**< 0.01, ^***< 0.001.