A Comparative Perspective on Extra-retinal Photoreception. (January 2019)

• Record Type: Journal Article
• Authors: Pérez, Jonathan H.; Tolla, Elisabetta; Dunn, Ian C.; Meddle, Simone L.; Stevenson, Tyler J.
• Is Part Of: Trends in endocrinology and metabolism. Volume 30:Number 1(2019)
• Page Start: 39
• Page End: 53
• Publication Date: 2019-01
• Subjects: extra-retinal photoreceptor -- OPN5 -- OPN4 -- VA-opsin -- brain; Endocrinology -- Periodicals; Metabolism -- Periodicals; Metabolism; 616.4
• DOI: 10.1016/j.tem.2018.10.005
• Languages: English
• ISSNs: 1043-2760

Abstract

Abstract : Ubiquitous in non-mammalian vertebrates, extra-retinal photoreceptors (ERPs) have been linked to an array of physiological, metabolic, behavioral, and morphological changes. However, the mechanisms and functional roles of ERPs remain one of the enduring questions of modern biology. In this review article, we use a comparative framework to identify conserved roles and distributions of ERPs, highlighting knowledge gaps. We conclude that ERP research can be divided into two largely unconnected categories: (i) identification and localization of photoreceptors and (ii) linkage of non-retinal light reception to behavioral and physiological processes, particularly endocrine systems. However, the emergence of novel gene editing and silencing techniques is enabling the unification of ERP research by allowing the bridging of this divide. Highlights: Light entrains rhythmic processes from daily patterns of hormone secretion and locomotor activity to annual neuroendocrine, metabolic, and behavioral cycles. Extra-retinal photoreception, through photosensitive opsin molecules, is a widespread phenomenon in non-mammalian vertebrates. Nearly a century of research has led to the identification of many different extra-retinal opsins. Extra-retinal photoreceptors are a key component in numerous physiological, metabolic, behavioral, and morphological changes in response to light stimulation, but the precise underlying mechanisms governing physiological and metabolic oscillations are largely unknown. Emerging techniques in gene editing and silencing are providing the necessary tools to finally establish the functional roles and mechanistic connections of extra-retinal opsins.