0049 Single Base Pair Change in Frizzled Affects Sleep State in Drosophila

Abstract Introduction Candidate polymorphisms for night sleep duration were previously identified based on differences between selectively bred long-sleeping and short-sleeping flies. A polymorphism found in an intron of the frizzled gene had a “G” allele associated to long sleep, and a “T” allele associated to short sleep. We sought to verify the effect of this polymorphism on sleep. Methods We used a long-sleeping line from the Sleep Inbred Panel (SIP), a group of 39 long- and short-sleeping lines, as our defined genetic background. We replaced the existing long-sleeping “G” allele with the short-sleeping “T” allele using CRISPR/Cas9 homology directed repair. This process created homozygous frizzled modified lines as well as sibling lines derived from three independent transformants. Sleep was measured using Trikinetics Drosophila Activity Monitors. Results Small but significant decreases in night sleep duration occurred in two of the three transformant lines with the “T” allele, losing 7.2 (P = 0.0349) and 7.9 (P = 0.0116) minutes of sleep, respectively. Applying a Hidden Markov Model demonstrated a significant difference in the time spent in different putative sleep states between frizzled modified and sibling lines. Flies with the long-sleeping “G” allele spent more time in putative deeper sleep states, while flies with the short-sleeping “T” allele spent more time in putative lighter sleep states. Conclusion These differences demonstrate that sleep in Drosophila is affected by a single base pair change in frizzled, as well as affecting specific sleep states. We are conducting bulk RNA sequencing on the brains of frizzled modified and sibling flies to determine whether changes in gene expression produced the change in sleep. Support (if any) This research was supported by the Intramural Research Program of the National Institutes of Health, the National Heart Lung and Blood Institute.