Circadian Behavioral and Bioluminescence Rhythms in the Per2 LUC Syrian Hamster

The use of genetically introduced optical reporters has improved understanding of circadian rhythms at the cellular and systems levels, but the use of this approach in mammals has been limited to mice and rats. The Syrian hamster ( Mesocricetus auratus ) has been a long-standing circadian model due to its rhythmic precision and physiological responses to photoperiod. Here we report the development of the Per2 LUC hamster, which harbors a knock-in construct inserted using the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology. We test circadian and photoperiodic function at the behavioral level in the Per2 LUC hamster and evaluate ex vivo Per2 -driven bioluminescence rhythms across a variety of tissues. Our results indicate modest effects of transgene insertion on circadian function in vivo and provide evidence that ex vivo Per2 -driven bioluminescence rhythms are robust to dissection for many of the 10 tissues examined here. Properties of bioluminescence rhythms varied by tissue type in the Per2 LUC hamster, which was overall similar to those displayed by tissues collected from the Per2 LUC mouse. Collectively, these results indicate that this new animal model may be beneficial in both circadian and non-circadian applications in future studies.