Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
Department of Biology, Faculty of Science, Okayama University, Okayama, 700-8530, Japan.
Biochem Biophys Res Commun. 2024 Apr 16;704:149705. doi: 10.1016/j.bbrc.2024.149705. Epub 2024 Feb 22.
The circadian clock in Drosophila is governed by a neural network comprising approximately 150 neurons, known as clock neurons, which are intricately interconnected by various neurotransmitters. The neuropeptides that play functional roles in these clock neurons have been identified; however, the roles of some neuropeptides, such as Trissin, remain unclear. Trissin is expressed in lateral dorsal clock neurons (LNds), while its receptor, TrissinR, is expressed in dorsal neuron 1 (DN1) and LNds. In this study, we investigated the role of the Trissin/TrissinR signaling pathway within the circadian network in Drosophila melanogaster. Analysis involving our newly generated antibody against the Trissin precursor revealed that Trissin expression in the LNds cycles in a circadian manner. Behavioral analysis further demonstrated that flies with Trissin or TrissinR knockout or knockdown showed delayed evening activity offset under constant darkness conditions. Notably, this observed delay in evening activity offset in Trissin flies was restored via the additional knockdown of Ion transport peptide (ITP), indicating that the Trissin/TrissinR signaling pathway transmits information via ITP. Therefore, this pathway may be a key regulator of the timing of evening activity offset termination, orchestrating its effects in collaboration with the neuropeptide, ITP.
果蝇的生物钟由一个由大约 150 个神经元组成的神经网络控制，这些神经元被称为生物钟神经元，它们通过各种神经递质错综复杂地相互连接。在这些生物钟神经元中发挥功能作用的神经肽已经被确定；然而，一些神经肽的作用，如 Trissin，仍然不清楚。Trissin 在侧面背时钟神经元（LNds）中表达，而其受体 TrissinR 在背神经元 1（DN1）和 LNds 中表达。在这项研究中，我们研究了果蝇中昼夜节律网络内的 Trissin/TrissinR 信号通路的作用。我们新生成的针对 Trissin 前体的抗体分析表明，LNds 中的 Trissin 表达呈昼夜节律循环。行为分析进一步表明，Trissin 或 TrissinR 敲除或敲低的果蝇在持续黑暗条件下表现出傍晚活动结束的延迟。值得注意的是，在 Trissin 果蝇中观察到的傍晚活动结束延迟通过额外的 Ion transport peptide (ITP) 敲低得到恢复，表明 Trissin/TrissinR 信号通路通过 ITP 传递信息。因此，该途径可能是傍晚活动结束终止时间的关键调节剂，与神经肽 ITP 协同发挥作用。
