A gonad-expressed opsin mediates light-induced spawning in the jellyfish Clytia
A gonad-expressed opsin mediates light-induced spawning in the jellyfish Clytia
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DOI：
10.7554/elife.29555
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发表时间：
2018-01-05
期刊：
影响因子：
7.7
通讯作者：
Houliston, Evelyn
中科院分区：
文献类型：
--
作者：
Artigas, Gonzalo Quiroga;Lapebie, Pascal;Houliston, Evelyn
在整个动物界，环境光信号广泛参与调节配子释放，但光响应机制的分子和细胞基础知之甚少。在水母中，产卵是由作用于性腺的暗-明或明-暗转变触发的，并由外胚层释放的卵母细胞成熟诱导神经肽激素(MIHS)介导。我们在Clytia hemisphaerica中确定，蓝蓝光会触发在分离的性腺中产卵。一个候选的视蛋白(Opsin9)被发现在特化的外胚层细胞中与MIH共表达。Opsin9由CRISPR/Cas9产生的敲除水母不能经历卵母细胞成熟和产卵，这是合成MIH可逆的表型。因此，Clytia中的配子成熟和释放是由性腺感光神经分泌细胞调节的，这些细胞通过Opsin9分泌MIH对光做出反应。祖先真核生物中类似的细胞可能允许对不同行为进行组织水平的光调节，这一特征在眼球动物中与视蛋白基因家族的扩张平行阐述。
Across the animal kingdom, environmental light cues are widely involved in regulating gamete release, but the molecular and cellular bases of the photoresponsive mechanisms are poorly understood. In hydrozoan jellyfish, spawning is triggered by dark-light or light-dark transitions acting on the gonad, and is mediated by oocyte maturation-inducing neuropeptide hormones (MIHs) released from the ectoderm. We determined in Clytia hemisphaerica that blue-cyan light triggers spawning in isolated gonads. A candidate opsin (Opsin9) was found co-expressed with MIH within specialised ectodermal cells. Opsin9 knockout jellyfish generated by CRISPR/Cas9 failed to undergo oocyte maturation and spawning, a phenotype reversible by synthetic MIH. Gamete maturation and release in Clytia is thus regulated by gonadal photosensory-neurosecretory cells that secrete MIH in response to light via Opsin9. Similar cells in ancestral eumetazoans may have allowed tissue-level photo-regulation of diverse behaviours, a feature elaborated in cnidarians in parallel with expansion of the opsin gene family.