Epigenetic process monitoring in live cultures with peptide biosensors.

Acetyltransferase is a member of the transferase group responsible for transferring an acetyl group from Acetyl-CoA to amino group of a histone lysine residue. Past efforts on histone acetylation monitoring involved biochemical analysis that do not pro-vide spatiotemporal information in a dynamic format. We propose a novel approach to monitor acetyltransferase acetylation in live single cells using Time Correlated Single Photon Counting Fluorescence Lifetime Imaging (TCSPC-FLIM) with peptide biosen-sors. Utilizing 2D and 3D cultures we show that the peptide sensor has a specific response to acetyltransferase enzyme activity in a fluorescence lifetime dependent manner (P<0.001). Our FLIM biosensor concept enables real-time longitudinal measurement of acetylation activity with high spatial and temporal resolution in live single cells to monitor cell function or evaluate drug effects to treat cancer or neurological diseases. Keywords: acetylation, FLIM, real-time detection, peptide sensor, live cultures.