Gene rhythm: how the circadian clock regulates 3D chromatin structure

EPFL biologists and geneticists have uncovered how the circadian clock orchestrates the 24-hour cycle of gene expression by regulating the structure of chromatin, the tightly wound DNA-protein complex of the cell. The work is published in Genes & Development. The circadian clock is an internal, biological "metronome" that dictates our 24-hour activity pattern. Biologically speaking, the circadian clock determines the synthesizing "rhythm" for a whole range of proteins that are involved in a multitude of biological processes that shift while we sleep or wake. In the cell, DNA is tightly wound around proteins in a complex called chromatin. This 3D structure compacts the DNA, prevents DNA damage and, critically, regulates gene expression. DNA folding allows the regions of DNA that initiates transcription, called promoters, to recruit distal (far away from promoters) DNA regions, called enhancers, to regulate gene expression.