Expression of mutant CHMP2B linked to neurodegeneration in humans disrupts circadian rhythms in Drosophila

Mutations in CHMP2B, an ESCRT‐III (endosomal sorting complexes required for transport) component, are associated with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Neurodegenerative disorders including FTD are also associated with a disruption in circadian rhythms, but the mechanism underlying this defect is not well understood. Here, we ectopically expressed the human CHMP2B variant associated with FTD (CHMP2B(Intron5)) in flies using the GMR‐GAL4 driver (GMR>CHMP2B(Intron5)) and analyzed their circadian rhythms at behavioral, cellular, and biochemical level. In GMR>CHMP2B(Intron5) flies, we observed disrupted eclosion rhythms, shortened free‐running circadian locomotor period, and reduced levels of timeless (tim) mRNA—a circadian pacemaker gene. We also observed that the GMR‐GAL4 driver, primarily known for its expression in the retina, drives expression in a subset of tim expressing neurons in the optic lobe of the brain. The patterning of these GMR‐ and tim‐positive neurons in the optic lobe, which appears distinct from the putative clusters of circadian pacemaker neurons in the fly brain, was disrupted in GMR>CHMP2B(Intron5) flies. These results demonstrate that CHMP2B(Intron5) can disrupt the normal function of the circadian clock in Drosophila.