posted on 2021-12-08, 18:39authored byYa Gong, Chujun Wei, Leonardo Cheng, Fengyi Ma, Shaoying Lu, Qin Peng, Longwei Liu, Yingxiao Wang
Histone
methylations play a crucial role in chromatin remodeling
and genome regulations. However, there is a lack of tools to visualize
these histone modifications with high spatiotemporal resolutions in
live cells. We have developed a biosensor based on fluorescence resonance
energy transfer (FRET) and incorporated it into nucleosomes, capable
of monitoring the trimethylation of H3K27 (H3K27me3) in live cells.
We also revealed that the performance of the FRET biosensor can be
significantly improved by adjusting the linkers within the biosensor.
An improved biosensor enables the live-cell imaging of different histone
methylation status, induced by the suppressive H3.3K27M or existing
in breast cancer cells with varying genetic backgrounds. We have further
applied the biosensor to reveal the dynamic coupling between H3K27me3
changes and caspase activity representing the initiation of apoptosis
in cancer cells by imaging both H3K27me3 and caspase activity simultaneously
in the same live cells. Thus, this new FRET biosensor can provide
a powerful tool to visualize the epigenetic regulation in live cells
with high spatial temporal resolutions.