PGC1α is a transcriptional co-activator regulating mitochondrial bioenergetics and oxidative metabolism and is highly expressed in cells with large energetic demands including photoreceptors.25,26 Further, lack of PGC1α renders photoreceptors susceptible to light damage.29 Given its crucial role in mitochondrial function, PGC1α has been identified as a therapeutic target for several neurodegenerative diseases.35, –37 Supporting this hypothesis, we provide evidence for transcriptional regulatory influence of MEF2D on PGC1α expression and for a neuroprotective role of PGC1α in photoreceptors. The gene discussed is MEF2D; the disease is neurodegenerative disease.