Fig. 1

Mutant human Tau^AT causes severe paralysis in C. elegans. a Bar diagram of Tau (2N4R, 441 residues, largest isoform in human CNS) with 2 inserts (N1, N2 near the N-terminus) and 4 repeats (R1-R4 in the C-terminal half) used to generate tau-transgenic lines. The point mutation A152T lies outside of the repeat domain in the proline rich region. The pan-neuronal promoter (Psnb-1) drives the expression of human tau cDNA in the C. elegans nervous system and the 3′UTR aids in tau expression. b Total worm lysates from synchronized day-3 old adults analyzed for Tau by western blotting using pan-tau antibody K9JA. Two independently integrated strains expressing Tau at comparably low and high levels were selected from each transgene: wild-type htau40 (Tau^wt-lo and Tau^wt-hi) and mutant htau40A152T (Tau^AT-lo and Tau^AT-hi). Tubulin serves as internal control. c Quantification of total tau in wild-type Tau lines (Tau^wt-lo and Tau^wt-hi) and mutant Tau-A152T lines (Tau^AT-lo and Tau^AT-hi). Error bars denote SEM. One-way ANOVA with Tukey’s test was applied for multiple comparisons (ns, non-significant, *P < 0.05, **P < 0.01). d Immunochemistry of whole worms with pan-tau K9JA antibody shows tau staining in the nervous system. Top panels depict nerve ring ganglion, bottom panels show ventral cord region. e Synchronized day-1 old adults were placed onto the centre of NGM plates freshly spotted with E. coli OP-50 and photographed after 10 min. Both Tau^AT-lo and Tau^AT-hi worms show strong paralytic phenotype apparent by their coiled body shape and lack of tracks on the E. coli lawn. The corresponding lines expressing wild-type human tau (Tau^wt-lo and Tau^wt-hi) possess a mild uncoordinated phenotype and are able to crawl away from the point of origin. f Thrashing assay of synchronized day-1 old adults in liquid. Control worms (non-tg control or worms expressing GFP in the pharynx as transformation marker only) display a high frequency of ~50 thrashes/30s. Worms expressing Tau^wt display a dose-dependent motor impairment with reduced thrashing frequency (~30/30s for Tau^wt -lo, ~20/30s for Tau^wt -hi). Motor impairment is very severe in the worms expressing mutant Tau^AT (both -lo and -hi, ~2/30s). One-way ANOVA with Tukey’s test was applied for multiple comparisons. Error bars denote SEM, n ≥ 30. (ns., non-significant, *P < 0.05, **P < 0.01, ***P < 0.001)