BIOCHEMICAL-CHARACTERIZATION OF TAU-PROTE INS DURING CEREBRAL AGING OF THE LEMURIAN PRIMATE MICROCEBUS-MURINUS

Tau proteins extracted from the brain of 12 adult microcebes ranging f rom 2 to 9 years old were characterized by Western blots, using immuno logical probes against normal and pathological human Tau proteins. In microcebes, the molecular weight of Tau proteins increases during agin g, with variants of 52-54, 64, 67 kDa in the young adult and variants of 60 and 70 kDa in the oldest animal studied. The increase of the app arent molecular weight is due to a change of conformation and a stabil ization in the ''hyperphosphorylated'' state, as revealed with phospho rylation-dependent monoclonal antibodies Tau-1 and AD2. Furthermore, A D1 specifically detected Alzheimer-type epitopes on the 60 kDa Tau iso form om a very old microcebe. These results suggest that Microcebus mu rinus is an interesting model for the study of the biochemical dysfunc tions that occur in the human brain during aging and Alzheimer disease .