Split GFP complementation assay for quantitative measurement of tau aggregation in situ

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Alzheimer disease is characterized by neurofibrillary tangles composed of aggregated tau protein.
• The toxic species in Alzheimer disease are likely intermediate forms of tau, not mature tangles.
• Monitoring tau aggregation in living cells is crucial for understanding disease progression.

Purpose of the Study:

• To develop a quantitative method for measuring tau aggregation in living cells.
• To understand the transition of tau from physiological to pathological forms.
• To evaluate factors influencing tau aggregation.

Main Methods:

• Established a split green fluorescent protein (GFP) complementation assay.
• Fused a tau-binding GFP fragment (GFP(11)) to tau protein.
• Coexpressed GFP(11)-tau with the larger GFP fragment (GFP(1-10)) in cells.
• Monitored changes in fluorescence to quantify tau aggregation.

Main Results:

• The assay successfully detected and quantified tau aggregation in living cells.
• Decreased fluorescence correlated with increased tau aggregation.
• The assay allows for real-time monitoring of tau aggregation dynamics.
• The method can be used with fluorescence microscopy and plate readers.

Conclusions:

• The split GFP complementation assay is a valuable tool for studying tau aggregation.
• This assay facilitates the investigation of factors modulating tau aggregation in real-time.
• Understanding tau aggregation dynamics is key to developing Alzheimer disease therapies.