The Clock:cycle complex is a major transcriptional regulator ofDrosophilaphotoreceptors that protects the eye from retinal degeneration and oxidative stress

Abstract

The aging eye experiences physiological changes that include decreased visual function and increased risk of retinal degeneration. Although there are transcriptomic signatures in the aging retina that correlate with these physiological changes, the gene regulatory mechanisms that contribute to cellular homeostasis during aging remain to be determined. Here, we integrated ATACseq and RNAseq data to identify 61 transcription factors that showed differential activity in aging Drosophila photoreceptors. These 61 age-regulated transcription factors include two circadian regulators, Clock and cycle, that showed sustained increased activity during aging. When we disrupted Clock activity in adult photoreceptors, we observed changes in expression of 15 to 20% of genes including key components of the phototransduction machinery and many eye-specific transcription factors. Using ATAC-seq, we showed that loss of Clock activity leads to changes in activity of 31 transcription factors and causes a progressive decrease in global levels of chromatin accessibility in photoreceptors. Supporting a key role for Clock-dependent transcription in the eye, disruption of Clock activity in photoreceptors also induced light-dependent retinal degeneration and increased oxidative stress, independent of light exposure. Together, our data suggests that the circadian regulators Clock and cycle act as neuroprotective factors in the aging eye by directing gene regulatory networks that maintain expression of the phototransduction machinery and counteract oxidative stress.

Establishing the contribution of active histone methylation marks to the aging transcriptional landscape of Drosophila photoreceptors

“…Drosophila stocks were raised and NIE and ChIP-seq performed as previously described 15,66 . The following genotypes were used: Rh1-Gal4>UAS-GFP KASH ( w 1118 ;; P{w +mC =[UAS-GFP-Msp300KASH}attP2, P{ry +t7.2 =rh1-GAL4}3, ry 506 ); Set2 RNAi (BDSC #42511; y 1 v 1 ; P{y +t7.7 v +t1.8 =TRiP.HMJ02076}attP40 ); mCherry RNAi ( yv; P{w v+ =[UAS-mCherry-RNAi]}attP2 ) 26 ; Rh1-luciferase ( P{w +mC =Rh1-Ffluc}3 ) 26 .…”