Genetic recording of in vivo cell proliferation by ProTracer

The ability to experimentally measure cell proliferation is the basis for understanding the sources of cells that drive organ development, tissue regeneration and repair. Recently, we generated a genetic approach to detect cell proliferation: we used genetic lineage-tracing technologies to achieve seamless recording of in vivo cell proliferation in a tissue-specific manner. We provide a detailed protocol (generation of mouse lines, characterization of mouse lines, mouse line crossing and cell-proliferation tracing) for using this genetic system to study cell proliferation. This cell-proliferation tracing system, which we term 'ProTracer' (Proliferation Tracer), permits lifelong noninvasive monitoring of cell proliferation of specific cell lineages in live animals. Compared with other short-term strategies that require execution of animals, ProTracer does not require sampling or animal sacrifice for tissue processing. To highlight these features, we used ProTracer to study the proliferation of hepatocytes during liver homeostasis and after tissue injury in mice. We show that the protocol is applicable to study any in vivo cell proliferation, which takes similar to 9 months to finish from mouse generation to data analysis. This protocol can easily be carried out by researchers skilled in mouse-related experiments. ProTracer is a genetic lineage-tracing technology that uses two recombinases to allow lifelong, noninvasive monitoring of cell proliferation for specific cell lineages in live animals.

Automated summary

The experimental measurement of cell proliferation is essential for understanding the origins of cells that drive the development of organs, tissue regeneration, and repair. We have recently developed a genetic approach called ProTracer that allows lifelong, noninvasive monitoring of cell proliferation in specific cell lineages in live animals. This system provides a detailed protocol for studying cell proliferation and can be easily implemented by researchers skilled in mouse-related experiments.