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NC3Rs: National Centre for the Replacement Refinement & Reduction of Animals in Research
Pilot study grant

EFucci an atlas of proliferation to reduce mouse usage in embryonic proliferation assays

Dr Richard Mort with colleagues by a low wall with trees in the background

At a glance

Award date
February 2014
Grant amount
Principal investigator
Dr Richard Mort


MRC Human Genetics Unit University of Edinburgh


  • Reduction
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Application abstract

The study of proliferation is key to the characterisation of many models of human disease especially in the developing embryo. There were over 3000 academic papers published in the field in 2013 alone. Often these studies use the incorporation of thymidine analogues into the DNA of dividing cells to identify sub-populations of cycling cells. This approach usually requires either multiple intraperitoneal injections of the thymidine analogue or the surgical implantation of mini osmotic pumps to slowly release the analogue. The Fucci system is an alternative to this approach that uses two genetically encoded biosensors of cell cycle phase to label cells and therefore does not require surgical intervention. We have developed an alternative mouse model that incorporates the Fucci probes into a single construct driven by a strong ubiquitously active promoter (R26Fucci2a). This has allowed us to reduce animal usage in our own experiments by abrogating the need to use two mouse lines, one expressing each Fucci probe. The atlas will also help to promote the use of our alternative R26Fucci2 model thus reducing the number of surgical procedures required to carry out the experiments.


  1. Ford MJ et al. (2018). A Cell/Cilia Cycle Biosensor for Single-Cell Kinetics Reveals Persistence of Cilia after G1/S Transition Is a General Property in Cells and Mice. Developmental Cell 47:4(509-523.e5). doi: 10.1016/j.devcel.2018.10.027