Nie Ke, Wang Kun, Huang Deng-Feng, Huang Yu-Bin, Yin Wu, Ren Da-Long, Wang Han, Hu Bing
a Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, School of Life Sciences , University of Science and Technology of China , Hefei , Anhui Province , P. R. China.
b Center for Circadian Clocks, Soochow University , Suzhou , Jiangsu , China.
Chronobiol Int. 2018 Feb;35(2):160-168. doi: 10.1080/07420528.2017.1391276. Epub 2017 Nov 20.
The circadian clock is an endogenous and entrainable time-keeping mechanism with a period of approximately 24 h, operated by transcription/translation feedback loops composed of circadian clock genes and their proteins. The visual system displays robust circadian changes. Relatively little, however, is known about the mechanisms underlying visual circadian rhythmicity. Zebrafish period1b (per1b), as a canonical circadian clock gene, is involved in circadian regulation. Here, we observed that zebrafish per1b mutants exhibit visual defects including reduced behavioral contrast sensitivity and significant retinal dopaminergic deficiency. Further, partially damaged dopaminergic interplexiform cells in wild-type larvae also led to reduced behavioral contrast sensitivity, while exogenous dopamine administration effectively restored the contrast sensitivity of per1b mutants. Taken together, these results suggest that retinal dopaminergic deficiency derived from loss of per1b results in visual defects in zebrafish.
per1b, period1b; per, period; per1, period1; per2, period2; per3, period3; ERG, electroretinogram; DA-IPCs, dopaminergic interplexiform cells; IRBP, interphotoreceptor retinoid binding protein; MS-222, methane-sulfonate; USTC, University of Science and Technology of China; OKR, optokinetic response; dpf, day postfertilization; 6-OHDA, 6-hydroxydopamine; TH, tyrosine hydroxylase; DA, dopaminergic; INL, inner nuclear; IPL, innerplexiform layers; hpf, hours postfertilization; cpd, cycle per degree; ADHD, attention deficit and hyperactivity disorder.
昼夜节律钟是一种内源性且可被调节的计时机制，周期约为24小时，由昼夜节律钟基因及其蛋白质组成的转录/翻译反馈环驱动。视觉系统呈现出明显的昼夜节律变化。然而，关于视觉昼夜节律的潜在机制，我们所知甚少。斑马鱼period1b（per1b）作为一个典型的昼夜节律钟基因，参与昼夜节律调节。在此，我们观察到斑马鱼per1b突变体表现出视觉缺陷，包括行为对比敏感度降低和视网膜多巴胺能显著缺乏。此外，野生型幼虫中部分受损的多巴胺能网间细胞也导致行为对比敏感度降低，而外源性多巴胺给药有效地恢复了per1b突变体的对比敏感度。综上所述，这些结果表明，per1b缺失导致的视网膜多巴胺能缺乏会引起斑马鱼的视觉缺陷。
per1b，period1b；per，period；per1，period1；per2，period2；per3，period3；ERG，视网膜电图；DA - IPCs，多巴胺能网间细胞；IRBP，光感受器间类视黄醇结合蛋白；MS - 222，甲磺酸盐；USTC，中国科学技术大学；OKR，视动反应；dpf，受精后天数；6 - OHDA，6 - 羟基多巴胺；TH，酪氨酸羟化酶；DA，多巴胺能；INL，内核层；IPL，内网层；hpf，受精后小时数；cpd，每度循环数；ADHD，注意力缺陷多动障碍
