estrogen-related receptor directs a transcriptional switch that supports adult glycolysis and lipogenesis.

Metabolism and development must be closely coupled to meet the changing physiological needs of each stage in the life cycle. The molecular mechanisms that link these pathways, however, remain poorly understood. Here we show that the estrogen-related receptor () directs a transcriptional switch in mid-pupae that promotes glucose oxidation and lipogenesis in young adults. mutant adults are viable but display reduced locomotor activity, susceptibility to starvation, elevated glucose, and an almost complete lack of stored triglycerides. Molecular profiling by RNA-seq, ChIP-seq, and metabolomics revealed that glycolytic and pentose phosphate pathway genes are induced by dERR, and their reduced expression in mutants is accompanied by elevated glycolytic intermediates, reduced TCA cycle intermediates, and reduced levels of long chain fatty acids. Unexpectedly, we found that the central pathways of energy metabolism, including glycolysis, the tricarboxylic acid cycle, and electron transport chain, are coordinately induced at the transcriptional level in mid-pupae and maintained into adulthood, and this response is partially dependent on , leading to the metabolic defects observed in mutants. Our data support the model that contributes to a transcriptional switch during pupal development that establishes the metabolic state of the adult fly.