A New Rhodopsin Influences Light-dependent Daily Activity Patterns of Fruit Flies
A New Rhodopsin Influences Light-dependent Daily Activity Patterns of Fruit Flies
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DOI：
10.1177/0748730417721826
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发表时间：
2017-10-01
影响因子：
3.5
通讯作者：
Helfrich-Foerster, Charlotte
中科院分区：
文献类型：
--
作者：
Kistenpfennig, Christa;Grebler, Rudi;Helfrich-Foerster, Charlotte
Rhodopsin 7 （Rh7）是一种新的无脊椎动物视紫红质基因，于2000年在黑腹果蝇的基因组中被发现，但其功能尚不清楚。我们通过P元素介导的诱变产生了一个Rh7缺失突变体（Rh7(0)），发现Rh7缺失对果蝇在光-暗（LD）循环中的活动模式有显著影响：Rh7(0)突变体比野生型对照表现出更少的早晨活动和更长的午睡时间。与这些结果一致，我们发现Rh7似乎在几个背时钟神经元中表达，这些神经元先前被认为与控制午睡有关。我们还在复眼的R8感光细胞和霍夫鲍尔-布希纳眼中发现了Rh7的表达，这些细胞已被证明可以控制运动活动的精确时间。单独缺乏Rh7既不会损害果蝇对恒定白光的反应，也不会损害它们跟随白光LD周期相移的能力。然而，在蓝光（470 nm）下，与野生型对照相比，Rh7(0)突变体需要更长的时间才能同步，这表明Rh7是一种蓝光敏感光色素，对生物钟同步的贡献很小。与缺乏基于隐花色素和/或基于眼睛的光输入到生物钟的突变体结合，Rh7的缺失引起了稍强的影响。
Rhodopsin 7 (Rh7), a new invertebrate Rhodopsin gene, was discovered in the genome of Drosophila melanogaster in 2000, but its function has remained elusive. We generated an Rh7 null mutant (Rh7(0)) by P element-mediated mutagenesis and found that an absence of Rh7 had significant effects on fly activity patterns during light-dark (LD) cycles: Rh7(0) mutants exhibited less morning activity and a longer siesta than wild-type controls. Consistent with these results, we found that Rh7 appears to be expressed in a few dorsal clock neurons that have been previously implicated in the control of the siesta. We also found putative Rh7 expression in R8 photoreceptor cells of the compound eyes and in the Hofbauer-Buchner eyelets, which have been shown to control the precise timing of locomotor activity. The absence of Rh7 alone impaired neither the flies' responses to constant white light nor the ability to follow phase shifts of white LD cycles. However, in blue light (470 nm), Rh7(0) mutants needed significantly longer to synchronize than wild-type controls, suggesting that Rh7 is a blue light-sensitive photopigment with a minor contribution to circadian clock synchronization. In combination with mutants that lacked additionally cryptochrome-based and/or eye-based light input to the circadian clock, the absence of Rh7 provoked slightly stronger effects.