Figure 2.

Absence of tau filaments in paralysed P301SxTAU62^on mice. (A) Immunoelectron microscopy shows HT7-positive tau filaments in total tau and sarkosyl extracts of brainstem tissue from a 6-month-old homozygous P301S mouse. (B) Total tau extract collected from a 3-week-old paralysed P301SxTAU62^on mouse reveals non-filamentous, oligomeric HT7 antibody positive tau structures while tau filaments are absent in its sarkosyl extract. (C) Absence of tau aggregates in a 3-week-old BL6 control mouse. The findings confirm that the severe neurotoxicity in P301SxTAU62^on mice does not depend on filamentous tau pathology, but is linked to hyperphosphorylated tau oligomers. Scale bar = 100 nm (A–C).