In this series of experiments, we have extended our previous observations to confirm the in vivo pathogenecity of Thr175Asp tau (tauT175D;a pseudophosphorylated tau construct mimicking pThr175 tau) and to demonstrate that the co-expression of mutant TDP-43 (TDP-43M337V) acts synergistically to significantly increase the neuropathological features of this experimental tauopathy. This evidence concerns the gene TARDBP and tauopathy.