Targeted modification of the Per2 clock gene alters circadian function in mPer2luciferase (mPer2Luc) mice
Fig 3
Genotype differences in OFA rhythms under LL following LD entrainment or DD exposure.
A. Representative records of mPer2Luc/Luc and WT control animals in LL following pre-exposure to LD12:12. B. Changes in periods of locomotor activity rhythm under LL exposure after entrainment to LD12:12. Periods were assessed in LL during the initial (1) and late (2) intervals (after 10 days in LL). mPer2Luc/Luc mice show a long period (>24 h) for the initial interval (1) in LL, which spontaneously switches to a short period (<24 h) during the late recording interval (2), whereas WT mice exhibit the long period throughout the experiment. C. Representative records of WT C57Bl6 control animals and mPer2Luc/Luc in LL following free-running in DD. D. Changes in periods of locomotor activity rhythm under LL after exposure to DD. Periods were assessed in LL during the initial (1) and late (2) intervals (after 2–3 weeks in LL). Periods in LL after pre-exposure to DD are long (>24 h) for both genotypes during the initial recording interval (1). During the late recording interval (2), the periods in some of mPer2Luc/Luc mice spontaneously switch to a short period (<24 h) but retain long throughout the recording in all WT mice. * = P < .05; ** = P < .01; **** = P < .0001.