Photoreceptor cells display a daily rhythm in the orphan receptor Esrrß.

ABSTRACT

PURPOSE: Nuclear orphan receptors are critical for the development and long-term survival of photoreceptor cells. In the present study, the expression of the nuclear orphan receptor Esrrß--a transcriptional regulator of energy metabolism that protects rod photoreceptors from dystrophy--was tested under daily regulation in the retina and photoreceptor cells. METHODS: The daily transcript and protein amount profiles were recorded in preparations of the whole retina and microdissected photoreceptor cells using quantitative PCR (qPCR) and western blot analysis. RESULTS: Esrrß displayed a daily rhythm with elevated values at night in the whole retina and enriched photoreceptor cells. Daily regulation of Esrrß mRNA depended on light input but not on melatonin, and evoked a corresponding rhythm in the Esrrß protein. CONCLUSIONS: The data presented in this study indicate that daily regulation of Esrrß in photoreceptor cells may contribute to their adaptation to 24-h changes in metabolic demands.