Factors other than hTau overexpression that contribute to tauopathy-like phenotype in rTg4510 mice

Abstract

The tauopathy-like phenotype observed in the rTg4510 mouse line, in which human tauP301L expression specifically within the forebrain can be temporally controlled, has largely been attributed to high overexpression of mutant human tau in the forebrain region. Unexpectedly, we found that in a different mouse line with a targeted-insertion of the same transgene driven by the same tetracycline-TransActivator (tTA) allele, but with even higher overexpression of tauP301L than rTg4510, atrophy and tau histopathology are delayed, and a different behavioral profile is observed. This suggests that it is not overexpression of mutant human tau alone that contributes to the phenotype in rTg4510 mice. Furthermore we show that the tauopathy-like phenotype seen in rTg4510 requires a ~70-copy tau-transgene insertion in a 244\u2009kb deletion in Fgf14, a ~7-copy tTA-transgene insertion in a 508\u2009kb deletion that disrupts another five genes, in addition to high transgene overexpression. We propose that these additional effects need to be accounted for in any studies using rTg4510.The rTg4510 mosue line has a tauopathy-like phenotype which is attributed to overexpression of human tau in the frontal cortex. Here the authors identify potential confounding genetic factors that could contribute to the phenotype.