Circadian Rhythms

All organisms exposed to sunlight possess a diurnal biological clock that controls a circadian rhythm of gene expression changes in most cell types. In mammals, for example, stimulation of the hypothalamic suprachiasmatic nucleus (SCN) in the brain by light mediates hormonal signaling to control the circadian rhythm in peripheral tissues. Interacting positive and negative feedback loops at the transcriptional and post-translational level ensure tight control over transcription factors regulating expression of the appropriate genes required during circadian days or nights. Although the circadian rhythm target genes vary widely from tissue to tissue, the transcription factors encoded by central clock and clock-controlled genes are mostly shared across all cell types. Genes regulated by circadian rhythms are involved in a diverse range of biological processes that affect physiology, metabolism, and behavior. Sleeping disorders (such as apnea, insomnia, and desynchronosis) disrupt the timing of the circadian clock causing fatigue. Continued disruption of the circadian clock is a source of bodily stress and a risk factor for cancer and cardiovascular disease. Analyzing the expression, regulation, and sequence of circadian rhythm genes can provide a better understanding of the regulation of the biological clock in all tissues and how its disruption affects normal processes and contributes to disease.

QIAGEN provides a broad range of assay technologies for circadian rhythm research that enables analysis of gene expression and regulation, epigenetic modification, genotyping, and signal transduction pathway activation. Solutions optimized for circadian rhythm studies include PCR array, miRNA, siRNA, mutation analysis, pathway reporter, chromatin IP, DNA methylation, and protein expression products.