Gene activity and DNA structure of the main internal body clock in mammals

Only 22% of cycling messenger RNA (mRNA) genes in the mammalian circadian clock are driven by new transcription.

• The circadian transcriptional cycle in mouse liver consists of three distinct phases: poised, transcriptional activation, and repressed.
• Transcription factor binding and RNA polymerase II recruitment exhibit a time-dependent pattern throughout the circadian cycle.
• Circadian modulation affects chromatin states on a genome-wide scale, surpassing previous observations from gene expression profiling.
• Both transcriptional and posttranscriptional mechanisms may play roles in regulating the mammalian circadian clock.

Simplified