Figure 8.

Transfection of neurons with Tau^GFP causes missorting of both exogenous and endogenous Tau. (A) Cortical neuron (7 DIV) transfected with hTau23^GFP lacking the two N-terminal inserts (see Figure 1, top). The exogenous Tau distributes into all compartments (axon indicated with arrows in A–C, dendrites indicated with arrowheads in A–C, soma), similar to the longest isoform used above. (B) Cells were stained with antibody SA4473 against the first insert, present only in endogenous Tau but not in the transfected Tau. The antibody stains not only axons but all compartments, indicating that the transfection of exogenous Tau leads to the missorting of endogenous and exogenous Tau. (C) Same field stained with MAP2 as a marker of soma and dendrites, illustrating that MAP2 maintains its normal sorting. (D) Blot showing that exogenous hTau40^D2 is recognized by antibody SA4473 against the first insert, but hTau23^GFP is not recognized, confirming the specificity of this antibody. Endogenous Tau is recognized in both cases. Actin is shown as a loading control.