Neurotoxicity of TDP-43 expression in <i>Drosophila melanogaster</i>.

<p>A) Scheme of constructs used for expression. Both constructs have an HA-tagged N-terminus. The nuclear localisation sequence (NLS) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031899#pone.0031899-Winton1" target="_blank">[39]</a> is indicated by two black rectangles between residues 82 and 98, the RNA-recognition motifs (RRM) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031899#pone.0031899-Winton1" target="_blank">[39]</a> or RNA-binding domains (RRM 1, between residues 106 and 175, and RRM2, between 191 and 262) are indicated by two gray rectangles, and the nuclear export sequence (NES) is represented by the black rectangle between residues 239 and 250 within RRM 2. Arrowheads indicate caspase cleavage sites at residues 89 and 219 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031899#pone.0031899-Buratti1" target="_blank">[40]</a>. B) Optical and scanning electron microscope images demonstrating the effects of the TDP-43 and TDP-25 constructs when expression is driven in the photoreceptor neurons with <i>gmr-GAL4</i>. Colour pictures represent optical micrographs, taken at 7.5× magnification, of fly eyes and flies of the same genotype imaged using a scanning electron microscope at 200× magnification are shown in the adjacent picture. Scale bars represent 20 µm. C) Low and high magnification confocal microscopy images of imaginal eye discs of third instar larvae expressing TDP-43 or TDP-25 in the photoreceptors under the control of <i>gmr-GAL4</i>. TDP-43 and TDP-25 distribution is shown by anti-HA (red) staining, anti-ubiquitin (green) reveals ubiquitinated species, and TOTO-3 (blue) reveals nuclei. White arrowheads indicate aggregates, white arrows indicate the location of the morphogenetic furrow, and white boxes represent the area shown at higher magnification. Low magnification scale bars = 100 µm and high magnification scale bars = 10 µm.