Effects Of Light Interruption On Sleep And Viability And Interaction Between Clock Proteins Timeless And Period In Drosophila Melanogaster

Light is a very important regulator to the daily sleep rhythm. Here, we investigate the influence of nocturnal light stimulation (discontinuous light stimulation, or DLS) on Drosophila sleep. Results showed that total daytime sleep was reduced due to a decrease in daytime sleep episode duration caused by DLS, but interestingly sleep was not strongly impacted at nighttime, although DLS occurred during the scotophase. During a subsequent recovery period without DLS, the sleep quality of nighttime sleep was improved and of daytime sleep reduced, indicating flies have a persistent response to DLS. Further studies showed that DLS damped the daily rhythm of a circadian light-sensitive protein CRY(cryptochrome) and the core clock protein TIM (timeless) both at the mRNA and protein levels. Moreover, DLS subsequently impacted reproduction, viability and other life factors of flies. These data indicate that the interaction of nocturnal light with the circadian clock plays an important role in sleep, reproduction and viability.PER (period) is the major transcription inhibitor in metazoan circadianclocks and lies at the center of several feedback loops that regulate gene expression. Dimerization of Drosophila PER and TIM influences nuclear translocation, repressor activity, and behavioral rhythms. The reseach about the relationship between PER and TIM become the hotspot. This research foucus on the functional relationship between PER and TIM. Results show that not only in cells level but also in vivo TIM505-578is the the functional domain, which carries out its function by preventing PER from phosphorylation degradation caused by DBT or others phosphokinase. HIS-tag pull down experiment show that the TIM505-578can bind PER1-512in vitro. This study provides a basis for analysis of their crystal structures and further function.