Molecular mechanism of circadian clock and its connection to neuropsychiatric disorders

Circadian rhythms, which are running with a period of 24 hours, are in mammals controlled via principal clock located in the area of suprachiasmatic nuclei (SCN) and peripheral oscillators. The basic molecular mechanism governing the circadian rhythms is the transcriptional-translational feedback loop of clock genes Clock, Bmal1, Per and Cry. The CLOCK-BMAL1 protein dimer acts as an activator for the transcription of the Per and Cry genes, which retroactively inhibit this dimer and thus its own transcription. This main loop affects other genes that are involved in regulation of the core loop. The function, nuclear localization and stability of clock genes are affected by a number of postranscriptional and postranslational modifications. Sleep disorders, one of the main processes controlled by the clock genes, accompany many neuropsychiatric disorders, including autism spectrum disorder. The development of these disorders have been associated with the clock genes or their interactions with other genes that play a major role in development of these disorders