Tau aggregates are RNA-protein assemblies that mis-localize multiple nuclear speckle components

We report the isolation and sequencing of tau aggregates from [1] HEK293 cells expressing Tau-RD-P301S-CFP/YFP that have been seeded with preformed fibrils from the brain of P301S mice (B6-Tg(Thy1-MAPT*P301S)2541; referred to as Tg2541 mice). Tau aggregates were isolated by differential centrifugation followed by fluorescence automated particle sorting using a BD FACSaraia. We found that these tau aggregates were enriched for particular small non-coding RNAs, including snoRNAs and snRNAs. [2] the following mice: FvBB6F1-Tg(Camk2a-tTa),(tetO-MAPT*wt)21221 (referred to as rTg21221 or WT tau mice in the paper) and FvBB6F1-Tg(Camk2a-tTA)1Mmay, (tet)-tdTomato-Syp/EGFP)1.1Luo/J,(tetO-MAPT*P301L)4510 (referred to as rTg4510 or P301L mice in the paper). Briefly, tau aggregates were isolated by 1% sarkosyl extraction (to enrich for insoluble proteins) followed by immunoprecipitation of tau using the tau-12 antibody (see Methods section of associated paper for further details). We found that these tau aggregates were enriched for particular small non-coding RNAs, including snRNAs and some snoRNAs. [3] Sequencing of HEK293 tau biosensor cells with and without tau aggregates reveals evidence of significant splicing alterations. Specifically we observed an increase in intron retention events in cells that contain tau aggregates relative to cells without tau aggregates. Examination of the RNA composition of tau aggregates in HEK293 cells [GSM4477465-GSM4477468] and from the brains of P301L mice (rTg4510) [GSM4484210-GSM4484221]. Examination of total RNA in HEK293 tau biosensor cells with and without tau aggregates [GSM5227473-GSM5227478].