Daily Expression of Six Clock Genes in Central and Peripheral Tissues of a Night-Migratory SongBird: Evidence for Tissue-Specific Circadian Timing
Daily Expression of Six Clock Genes in Central and Peripheral Tissues of a Night-Migratory SongBird: Evidence for Tissue-Specific Circadian Timing
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DOI：
10.3109/07420528.2013.810632
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发表时间：
2013-11
影响因子：
2.8
通讯作者：
Devraj Singh;S. Rani;Vinod Kumar
中科院分区：
文献类型：
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作者：
Devraj Singh;S. Rani;Vinod Kumar
在鸟类中，独立的昼夜节律钟位于视网膜、松果体和下丘脑中，它们相互作用并在功能水平上产生昼夜节律时间。然而，人们对分子时钟机制以及鸟类中央和外围时钟之间的整合知之甚少。本研究通过监测五个核心时钟基因（Per 2.哭泣1。哭泣2。Bmal 1和Clock）和一个时钟控制的基因（E4 bp 4）在夜间迁徙的鸣禽，红头（rb; Emberiza bruniceps）。作者首先部分克隆了这六个基因，然后测量了它们在中央（视网膜，下丘脑）和外周（肝脏，心脏，胃，肠道，睾丸）组织中的24小时谱，这些组织在12小时：12小时光-暗循环的六个时间（Zeitgeber时间2 [ZT 2]，ZT 6，ZT 11，ZT 13，ZT 18和ZT 23; ZT 0 =开灯）从鸟类（n = 5/ZT）收集。rbPer2. rbCry1。rbBmal 1和rbClock在所有组织中以显著的节律表达，除了在视网膜（仅rbClock）和睾丸中。然而，rbCry 2具有组织特异性表达模式：下丘脑，心脏和肠道中有显著的节律，但在视网膜，肝脏，胃和睾丸中没有。rbE 4 bp 4在除视网膜外的其他组织中均呈现明显的mRNA表达节律。此外，rbPer 2 mRNA峰与光照一致，而rbCry 1 mRNA峰与光照一致。rbBmal 1和rbE 4 bp 4 mRNA峰在关灯时相位对齐。rbCry 2和rbClock具有组织特异性散射峰。例如，在下丘脑中，rbCry 2和rbClock峰值分别接近rbCry 1和rbBmal 1峰值，但在其他组织中则不然。结果是一致的自动调节昼夜节律的反馈回路，并表示一个保守的组织水平的昼夜节律的时间代在buntings。形成反馈环的正肢和负肢的基因对之间的可变相位关系可能表明个体核心昼夜节律基因在昼夜节律时间生成中的组织特异性贡献。
In birds, independent circadian clocks reside in the retina, pineal, and hypothalamus, which interact with each other and produce circadian time at the functional level. However, less is known of the molecular clockwork, and of the integration between central and peripheral clocks in birds. The present study investigated this, by monitoring the timed expression of five core clock genes (Per2. Cry1. Cry2. Bmal1, and Clock) and one clock-controlled gene (E4bp4) in a night-migratory songbird, the redheaded bunting (rb; Emberiza bruniceps). The authors first partially cloned these six genes, and then measured their 24-h profiles in central (retina, hypothalamus) and peripheral (liver, heart, stomach, gut, testes) tissues, collected at six times (zeitgeber time 2 [ZT2], ZT6, ZT11, ZT13, ZT18, and ZT23; ZT0 = lights on) from birds (n = 5 per ZT) on 12 h:12 h light-dark cycle. rbPer2. rbCry1. rbBmal1, and rbClock were expressed with a significant rhythm in all the tissues, except in the retina (only rbClock) and testes. rbCry2, however, had tissue-specific expression pattern: a significant rhythm in the hypothalamus, heart, and gut, but not in the retina, liver, stomach, and testes. rbE4bp4 had a significant mRNA rhythm in all the tissues, except retina. Further, rbPer2 mRNA peak was phase aligned with lights on, whereas rbCry1. rbBmal1, and rbE4bp4 mRNA peaks were phase aligned with lights off. rbCry2 and rbClock had tissue-specific scattered peaks. For example, both rbCry2 and rbClock peaks were close to rbCry1 and rbBmal1 peaks, respectively, in the hypothalamus, but not in other tissues. The results are consistent with the autoregulatory circadian feedback loop, and indicate a conserved tissue-level circadian time generation in buntings. Variable phase relationships between gene pairs forming positive and negative limbs of the feedback loop may suggest the tissue-specific contribution of individual core circadian genes in the circadian time generation.