The binding sites of E2F transcription factor inDrosophilametabolic genes are functionally distinct

ABSTRACTThe canonical role of the transcription factor E2F is to control the expression of cell cycle genes by binding to the E2F sites in their promoters. However, the list of putative E2F target genes is extensive and includes many metabolic genes, yet the significance of E2F in controlling expression of these genes remains largely unknown. Here, we used the CRISPR/Cas9 technology to introduce point mutations in the E2F sites upstream of five endogenous metabolic genes inDrosophila. We found that the impact of these mutations on both the recruitment of E2F and the expression of the target genes varied, with the glycolytic gene,Phosphoglycerate kinase(Pgk), being mostly affected. The loss of E2F regulation onPgkgene led to a decrease in glycolytic flux, TCA cycle intermediates levels, ATP content and an abnormal mitochondrial morphology. Remarkably, chromatin accessibility was significantly reduced at multiple genomic regions inPgkΔE2Fmutants. These regions contained hundreds of genes, including metabolic genes that were downregulated inPgkΔE2Fmutants. Moreover,PgkΔE2Fanimals had shortened life span and exhibited defects in high-energy consuming organs, such as ovaries and muscles. Collectively, our results illustrate how the pleiotropic effects on metabolism, gene expression and development in thePgkΔE2Fanimals underscore the importance of E2F regulation on a single E2F target,Pgk.