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The functional role of neuropsin and vertebrate ancient opsin for the photoperiodic response in Japanese quail.

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Conference

ConferenceOxford Chronobiology and Sleep Medicine Summer School
CountryUnited Kingdom
CityOxford
Period2/09/187/09/18
Internet address

Abstract

For over a century, it has been known that birds possess photoreceptors in the brain, coupled to a circadian clock, that are critical for the annual photoperiodic response in birds. However, the identity of the specific photopigment(s) involved in this response is still unknown. To date, three candidate opsins have been implicated as the deep brain photoreceptor: melanopsin (Opn4), neuropsin (Opn5) and vertebrate ancient opsin (VA opsin). This project aims to (1) use in situ hybridisation and immunocytochemistry techniques to localise the neuroanatomical distribution of the photoreceptors in the canary (Serinus canaria) and Japanese quail (Coturnix japonica), and (2) conduct in vivo RNAi manipulations to assess the functional role of Opn5 and VA opsin in quail. The hypothesis tested was disruption of VA opsin would prevent the photoinduced change in key neuroendocrine genes, gonadal hormones and reproductive recrudescence in Japanese quail. Using antibodies that target Opn5 and VA opsin, immunoreactive cells exhibited a diverse expression in the canary brain. There was robust Opn5 immunoreactivity in the paraventricular organ, along the ependymal layer in the 3rd ventricle and lateral ventricle. Unlike previous reports, VA opsin immunoreactive cells were identified in the ventral ependymal layer. Current work aims to confirm Opn5 and VA opsin immunoreactive distribution using in situ hybridization to identify the location of mRNA. To address the second aim, adeno-associated viral constructs that contain a short hair-pin loop to specifically inhibit Opn5 and VA opsin expression have been developed. Moreover, we will use intracerebroventricular injections that target the mediobasbal hypothalamus to selectively disrupt photoreceptor expression and examine the impact on the Japanese quail reproductive photoperiodic response. Our findings will finally elucidate the brain photoreceptor(s) that control seasonal rhythms in avian reproduction.

Research supported by the Leverhulme Trust

Event

Oxford Chronobiology and Sleep Medicine Summer School

2/09/187/09/18

Oxford, United Kingdom

Event: Conference

ID: 57321819