MAPT and tauopathy: To test this hypothesis we crossed human mutant P301L tau transgenic mice (line JNLP3, herein called ‘tau transgenic’, a model for a genetic form of a pure tauopathy [7]; all described mouse experiments have been approved by the Palo Alto Veterans Hospital Institutional Review Board for Animal Experiments) with transgenic mice overexpressing a soluble form of the murine complement receptor 1-related gene/protein y (sCrry) [8] (Figure 1A).