ELDR-Glo, a biosensor for cell age and quiescence depth

Area of Science:

• Cell Biology
• Molecular Biology
• Biotechnology

Background:

• Fluorescent reporters effectively show heterogeneity in proliferating cells.
• Analyzing quiescent (G0) cell differences is challenging but vital for development, tissue repair, and cancer research.
• Existing methods struggle to directly measure cell age or quiescence depth in diverse cell types and tissues.

Purpose of the Study:

• To introduce ELDR-Glo, a genetically-encoded fluorescent biosensor for estimating relative cell age in quiescent cells.
• To provide a tool for quantifying quiescence depth, a measure of time since cell cycle arrest.
• To enable the study of intercellular heterogeneity in quiescent cell populations.

Main Methods:

• Development of a genetically-encoded fluorescent biosensor (ELDR-Glo).
• Integration of replication-coupled degradation (S phase) with a slow-maturing mCherry and a normalization module.
• Validation using live-cell imaging and fixed-cell analysis, compatible with multiplexed immunofluorescence and flow cytometry.

Main Results:

• ELDR-Glo signal accurately correlates with true relative cell age.
• The biosensor successfully distinguishes between early and late quiescent (G0) cells.
• ELDR-Glo functions as a reliable in situ reporter for quiescence depth.

Conclusions:

• ELDR-Glo offers a novel and scalable method for assessing relative cell age and quiescence depth.
• This biosensor facilitates the investigation of cell proliferation control and quiescence heterogeneity.
• ELDR-Glo is a valuable tool for research in developmental biology, tissue maintenance, and oncology.