Memeli sirkadyen saatinde kriptokrom 1'i stabilize eden bir küçük molekülün karakterizasyonu

In most organisms, several physiological and behavioral mechanisms are regulated in a circadian rhythm-dependent manner. The mammalian circadian clock is generated by negative and positive transcriptional-translational feedback loops (TTFL), which consists of BMAL1, CLOCK, Periods (PER) and Cryptochromes (CRY) at the molecular level. At the positive arm of the TTFL loops, BMAL1 and CLOCK form a dimer and bind to E-box elements to initiate the transcription of the clock-controlled genes (CCGs) including the Per and Cry genes. Within the time Cry1/2 and Per1/2/3 accumulate in the cytosol and then translocate into the nucleus along with Casein kinase I epsilon/delta. They interact with BMAL1:CLOCK heterodimer and repress their activity and, in turn, repress the transcription of the CCGs. In mammals, 43% of the protein-coding genes are clock-controlled and transcribed rhythmically in at least one tissue. Therefore, disruption of the circadian clock as a result of circadian misalignment or genetic factors will be expected to greatly affect most of the physiological systems. In fact, several different diseases are shown to be linked to circadian disruption such as sleep disorders, metabolic and neural diseases, and cancer progression. That's why several groups have initiated drug discovery studies to find molecules that regulate the circadian clock for the treatment of these diseases. In this thesis, I characterized a novel small molecule (M54) specific for the core clock protein CRY1 in vitro level. M54 is discovered by an in silico approach called structure-based drug designing (SBDD) and predicted to bind to the primary pocket of CRY1. The primary pocket is important for the regulation of CRY stability due to interactions with the E3 ubiquitin ligases (FBXL3 and 21). I showed that M54 significantly increases the circadian period in a dose-dependent manner at the cellular level. Further biochemical studies demonstrated that M54 increases the stability of the CRY1. This study offers a new avenue as a therapeutic approach for patients who suffer from circadian clock-related disorders associated with dampened CRY1 levels.