Figure 6: 5K-A tau displays unique self-aggregating properties.

a. Schematic description of secondary passaging paradigm. Briefly, HEK293T cells expressing 5K-A tau constructs were either seeded with AD-tau, PSP-tau, or left unseeded. The detergent-insoluble fraction was harvested and used again (‘secondary 5K-A seeds’) for seeding of WT tau or P301L tau. b. Representative immuno-EM images of total tau antibody-stained detergent-insoluble 5K-A tau seeded with either AD-tau, PSP-tau, or unseeded. All filaments were stained with 10nm gold conjugated secondary antibody followed by negative staining with 1% uranyl acetate. Arrows depict 10nm gold particles. Additional EM images for each condition are shown in Fig. S4. c-d. Representative total tau and AT8-tau blots depicting outcomes of secondary passaging of 5K-A seeds on WT tau and P301L tau. e. Characterization of the phosphorylation profile for primary passaged 5K-A tau seeds (top row) and secondary passaged 5K-A seeds on P301L tau (bottom row). Representative blots from n=2 replicates.