The video demonstrates a fluorescence resonance energy transfer (FRET) flow cytometry assay to detect the seeding activity of protein aggregates isolated from biological samples. Mammalian cells expressing tau reporter proteins are incubated with liposome transduction complexes containing tau seeds. These seeds mediate the aggregation of the reporter proteins, leading to generating a FRET positive signal in the flow cytometer.
Protocol
NOTE: This protocol emphasizes the use of FRET flow cytometry for detecting seeding activity from mouse biological samples. It is also compatible with recombinant fibrils and human biological samples. Mouse euthanasia and brain harvesting was performed in accordance with IACUC-approved procedures. 1. Brain Extraction Following deep anesthetization with isoflurane (2%), perfuse a mouse with ice-cold PBS containing 0.03% heparin, and extract the brai…
Representative Results
Table 1: Cell lines used with FRET flow cytometry. HEK 293T cells are used for flow cytometry setup. CFP single-positive cells are used for compensation (*). YFP single-positive cells are used to eliminate false FRET signal due to direct activation of YFP by 405 nm excitation. CFP/YFP dual-positive cells are FRET-compatible and serve as the biosensor cells. <img al…