Fig. 2
From: The functional significance of the skeletal muscle clock: lessons from Bmal1 knockout models
Changes in gene expression induced by muscle-specific Bmal1 knockout (mKO), leading to disruption of the muscle clock, or denervation (D), leading to loss of motor activity. Transcript levels were monitored by qPCR every 4Â h (0, lights on; 12, lights off). Three representative genes are illustrated. Dbp, a direct target of Bmal1, is strongly repressed by Bmal1 KO but shows only a phase advance of around 4Â h in denervated muscles without any change in oscillation amplitude. In contrast, Rcan1.4, a gene controlled by motor neuron activity via calcineurin-NFAT signaling, is essentially unchanged in Bmal1 mKO muscles but is drastically downregulated by denervation. Myod1, coding for the myogenic regulatory factor MyoD, shows an atypical response, with circadian oscillation maintained with increased amplitude in both Bmal1 mKO and denervated muscles. In denervation experiments, the muscles were removed 7Â days after sciatic nerve section. The muscles examined were tibialis anterior for Dbp and Myod1 and soleus for Rcan1.4 (data from [27]; changes in Myod1 are unpublished observations)