This weekend, clocks in the UK will ‘fall back’ one hour; a week later, the US will follow. This sudden change might leave you feeling slightly discombobulated, but chances are, your internal clock will soon adjust to compensate. Some people aren’t so lucky; perturbations of circadian rhythm are thought to be a factor in sleep disorders and some psychiatric conditions like bipolar disorder, according to a study published last month in PLoS One.

The master timekeeper of the body is in the suprachiasmatic nuclei (SCN), a tiny pair of neuron clusters located in the hypothalamus. But there are also peripheral body clocks, located in organs like the liver, and even within individual cells. Synchronizing these clocks means taking non-environmental cues, like feeding patterns, into account.

A recent paper in Cell described how an enzyme called poly (ADP-ribose) polymerase 1 (PARP1) coordinates the master clock of the SCN with circadian rhythmic gene expression in the liver. Mice deficient in PARP1 were slower to respond when their feeding regimen changed. The authors also found that PARP1 interacts with two key circadian rhythm regulators, CLOCK and BMAL-1. These transcription factors were also recently found to be involved in muscle maintenance by targeting MyoD, a master regulating protein of myogenesis.

Though researchers have been able to peer into the circadian clocks of model organisms like mice and fruit flies, it was unclear whether or not the nematode Caenorhabditis elegans had a circadian rhythm at all. A genome-wide analysis in PLoS Biology found the first evidence of gene expression patterns in C. elegans influenced by circadian rhythm. The authors found that temperature and light influenced the expression of up to 9% and 4% of all the genes in the organism.

Enjoy the extra hour of sleep!

Image by stevendepolo via Flickr Creative Commons