Poor Sleep Quality Is Associated with Dawn Phenomenon and Impaired Circadian Clock Gene Expression in Subjects with Type 2 Diabetes Mellitus

Figure 4

The core mechanism of a circadian clock gene. The CLOCK–BMAL1 heterodimer is the core of circadian clock. It stimulates the transcription of period (PERs, including PER1, PER2, and PER3) and cryptochrome (CRYs, including CRY1 and CRY2). Soon afterwards, PERs and CRYs translocate to the nucleus and inhibit CLOCK–BMAL1 activity.