The Ion Transport Peptide Is a New Functional Clock Neuropeptide in the Fruit Fly Drosophila melanogaster
The Ion Transport Peptide Is a New Functional Clock Neuropeptide in the Fruit Fly Drosophila melanogaster
复制标题
DOI：
10.1523/jneurosci.0111-14.2014
复制
发表时间：
2014-07-16
影响因子：
5.3
通讯作者：
Helfrich-Foerster, Charlotte
中科院分区：
文献类型：
--
作者：
Hermann-Luibl, Christiane;Yoshii, Taishi;Helfrich-Foerster, Charlotte
黑腹果蝇的时钟网络表达多种神经肽，但迄今为止仅发现神经肽色素分散因子（PDF）在时钟介导的行为控制中具有功能。在这里，我们提出了离子转运肽（ITP）的行为节律的控制中的作用，这是在第五个小腹侧神经元，一个背侧神经元，并在只有少数nonclock细胞在大脑中表达。免疫细胞化学分析表明，ITP，PDF一样，最有可能是释放在背侧前脑的投射终端的节奏。这种节律在恒定的黑暗条件下继续，表明ITP的释放是时钟控制的。ITP表达在低形态突变体Clk（AR）中减少，表明ITP表达受CLOCK调节。使用基因编码的RNAi构建体，我们敲低了两个时钟细胞中的ITP，发现这些果蝇显示出夜间活动减少和夜间活动增加。ITP与两个独立的无时间GAL4线的过度表达完全打乱了行为节奏，但只有轻微的抑制PER循环在重要的起搏器神经元，表明ITP的作用在时钟输出通路，而不是在时钟网络内的通信。ITP和PDF的同时敲除（KD）使果蝇在恒定条件下过度活跃，几乎完全无菌。在光暗条件下，双KD结合了单KD果蝇的行为特征。此外，它减少了苍蝇的睡眠。我们的结论是ITP和PDF是时钟的主要输出信号，合作控制苍蝇的活动节奏。
The clock network of Drosophila melanogaster expresses various neuropeptides, but a function in clock-mediated behavioral control was so far only found for the neuropeptide pigment dispersing factor (PDF). Here, we propose a role in the control of behavioral rhythms for the ion transport peptide (ITP), which is expressed in the fifth small ventral lateral neuron, one dorsal lateral neuron, and in only a few nonclock cells in the brain. Immunocytochemical analyses revealed that ITP, like PDF, is most probably released in a rhythmic manner at projection terminals in the dorsal protocerebrum. This rhythm continues under constant dark conditions, indicating that ITP release is clock controlled. ITP expression is reduced in the hypomorph mutant Clk(AR), suggesting that ITP expression is regulated by CLOCK. Using a genetically encoded RNAi construct, we knocked down ITP in the two clock cells and found that these flies show reduced evening activity and increased nocturnal activity. Overexpression of ITP with two independent timeless-GAL4 lines completely disrupted behavioral rhythms, but only slightly dampened PER cycling in important pacemaker neurons, suggesting a role for ITP in clock output pathways rather than in the communication within the clock network. Simultaneous knockdown (KD) of ITP and PDF made the flies hyperactive and almost completely arrhythmic under constant conditions. Under light-dark conditions, the double-KD combined the behavioral characteristics of the single-KD flies. In addition, it reduced the flies' sleep. We conclude that ITP and PDF are the clock's main output signals that cooperate in controlling the flies' activity rhythms.