Omnis automated immunostainer

Formalin fixed paraffin embedded tissue sections (5μm thick) were acquired through the Alzheimer’s Disease Research Center at the Massachusetts General Hospital (Charlestown, MA) or the University of British Columbia (^{41 (link)}, Vancouver, Canada). Available demographics information for the three de-identified cases used in the current study can be found in Supplemental Table 1. Tissues were stained and processed by multiple approaches. For the images in the main text Figure 7, the protocol described in Lee et al was used with anti-FUS (Sigma Aldrich, HPA008784), together with either a hematoxylin nuclear counterstain for immunohistochemistry or a DAPI nuclear counterstain for immunofluorescence^{64 (link)}. For the images in Supplemental Figure 17, mouse anti-Nup62 (BD Bioscience, BDB610497) was diluted to 1:150^{47 (link)}. Immunohistochemistry was performed using the Dako Omnis automated immunostainer with primary incubation for 60 mins following heat-induced antigen retrieval and developed using Dako Envision Flex/HRP. Data collection and analysis were not performed blind to the conditions of the experiment