Drosophila CG3303 is an essential endoribonuclease linked to TDP-43-mediated neurodegeneration

Laneve, Pietro; Piacentini, Lucia; Casale, Assunta Maria; Capauto, Davide; Gioia, Ubaldo; Cappucci, Ugo; Di Carlo, Valerio; Bozzoni, Irene; Di Micco, Patrizio; Morea, Veronica; Di Franco, Carmela Antonia; Caffarelli, Elisa

To investigate whether the immature phenotype could be ascribed to an impaired synaptic input to CCAP/ bursicon neurons, we silenced dendoU expression in cholinergic neurons 16 . We used choline acetyltransferase (Cha) promoter-driven GAL4, which is expressed in both central and sensory cholinergic neurons. DendoU downregulation resulted in the same immature phenotypes observed in pan-neuronal knockdown ( Fig. 5a and Supplementary Table 2 ). This result indicates that dendoU-linked immature phenotype can be, at least partially, ascribed to cholinergic DendoU function. DendoU silencing in cholinergic neurons also produces relevant effects on median lifespan, with 75% decrease (31.06 ± 0.37 days for control flies vs 7.57 ± 0.18 days for cha-G4 > dendoU RNAi ) ( Fig. 5b and Supplementary Table 2) , and locomotion, with 70% reduction (Fig. 5c and Supplementary Table 2 ). To verify whether DendoU effect on locomotion is cell-autonomous, functional inactivation of dendoU in motor neurons was performed by the specific D42-GAL4 driver. Climbing assays showed 25% decrease of performance index (Fig. 5d and Supplementary Table 2) , indicating the involvement of DendoU in motor neuron activity. Moreover, dendoU silencing in motor neurons caused a low frequency of altered phenotypes, i.e. 3% of immature phenotype and 7% of mild immature phenotypes (unexpanded wings), and 30% decrease of median lifespan (31.38 ± 0.26 days for control flies vs 21.53 ± 0.50 days for D42-G4 > dendoU RNAi flies) (Fig. 5e and Supplementary Table 2 ).