PSEN1 and amyloidosis: To define changes to astrocytic gene expression in response to amyloid or tau pathology, we performed translating-ribosome-affinity purification (TRAP) on astrocytes, by crossing the MAPTP301S and APP/PS1 mice onto the TRAP line Aldh1l1_eGFP-RPL10a (Fig. 1A), which expresses GFP-tagged ribosomes specifically in astrocytes17, showing co-localisation with astrocyte markers Aldh1l1 and GFAP, but not neuronal or microglial markers (Supplementary Fig. 1A, B).