Question: Is c-myc subject to regulation by the circadian clock?

Context:
The current study encompasses the investigation of simultaneous expression of four circadian clock genes (Bmal1, Clock, Per1 and Per2) and three clock-controlled cell cycle genes (Myc, Cyclin D1 and Wee1)
Our results suggest that aberrant expression of circadian clock genes can lead to aberrant expression of their downstream targets that are involved in cell proliferation and apoptosis and hence may result in manifestation of CLL.
Loss of Bmal1 reduced the expression of per1, per2, per3, wee1 and p53. The expression of p21 and c-myc was also altered in certain cell lines.
In particular, the proto-oncogene c-Myc has been documented to be under circadian regulation.
The circadian expression of c-MYC is modulated by the histone deacetylase inhibitor trichostatin A in synchronized murine neuroblastoma cells.
Our results, using the murine neuroblastoma cell line N2A, show that Per1 and c-Myc steady-state mRNA levels oscillate with the same phase.
These experiments demonstrate for the first time that a significant decrease in c-Myc transcript and protein levels can be achieved after a short TSA treatment applied only at specific circadian times. This is also followed by a reduction in the proliferation rate of the cell population.
Among the circadian output pathways, the rhythmic sympathetic signaling plays a key role in the central-peripheral timing mechanism that simultaneously activates the cell cycle clock via AP1-controlled Myc induction and p53 via peripheral clock-controlled ATM activation.
Jet-lag promptly desynchronizes the central clock-SNS-peripheral clock axis, abolishes the peripheral clock-dependent ATM activation, and activates myc oncogenic potential, leading to tumor development in the same organ systems in wild-type and circadian gene-mutant mice.
The results showed that over-expression of Per2 induced not only cell cycle arrest at G2/M phase but also an increase in apoptosis, which was confirmed by characteristic morphological changes, FCM and evident DNA fragmentation. Further experiments confirmed both up-regulation of P53 and down-regulation of CylinB1and C-myc.
On the other hand, while P53 was found to be down-regulated. CylinB1 and C-myc were up-regulated. after Per2 knockdown.
We also show that BMAL1 epigenetic inactivation impairs the characteristic circadian clock expression pattern of genes such as C-MYC, catalase, and p300 in association with a loss of BMAL1 occupancy in their respective promoters.
Per2 mutant (Per2(m/m)) mice show an increase in lymphomas and deregulated expression of cyclin D and c-Myc genes that are key to proliferation control.
The expression of cell cycle genes such as Wee1, Cyclins, and c-Myc are under circadian control and could be directly under the regulation of the circadian transcriptional complex.
Overexpressed mPER2 also altered the expression of apoptosis-related genes. The mRNA and protein levels of c-Myc, Bcl-X(L) and Bcl-2 were downregulated,
Temporal expression of genes involved in cell cycle regulation and tumor suppression, such as c-Myc, Cyclin D1, Cyclin A, Mdm-2 and Gadd45alpha is deregulated in mPer2 mutant mice.
The temporal expression of genes involved in cell cycle regulation and tumor suppression, such as c-Myc, Cyclin D1, Cyclin A, Mdm-2, and Gadd45alpha, is deregulated in mPer2 mutant mice.

Answer: Yes, the expression of c-myc is regulated by the circadian clock protein Per2.
Exact answer: yes