Transplanted Drosophila excretory tubules maintain circadian clock cycling out of phase with the host
Transplanted Drosophila excretory tubules maintain circadian clock cycling out of phase with the host
复制标题
DOI：
10.1016/s0960-9822(00)00299-2
复制
发表时间：
2000-01-27
期刊：
影响因子：
9.2
通讯作者：
Hege, DM
中科院分区：
文献类型：
--
作者：
Giebultowicz, JM;Stanewsky, R;Hege, DM
行为和生理过程中的昼夜节律是由保守的分子机制驱动的，涉及动物大脑中时钟基因的节律性表达[I]，体外外周组织中类似分子节律的持续性[2，3]表明这些组织包含可能与节律性生理功能相关的自我维持的昼夜节律钟。目前还不知道大脑和外围时钟是如何组织成一个同步的计时系统的;然而，已经假设外围时钟服从大脑中的主时钟。为了解决这个问题，我们研究了两个时钟基因，周期（每）和无时间（蒂姆），在宿主和移植的果蝇腹部器官的表达。我们发现，组织培养的排泄器官显示per和tim基因活性的自由运行的光敏感振荡，表明它们具有自我维持的生物钟。为了测试体液因素，我们监测了移植到宿主果蝇中的排泄小管中TIM蛋白质的循环，该蛋白质被带入相反的光暗循环。我们发现，供体小管中的时钟蛋白与宿主小管中的时钟蛋白周期异相，这表明尽管共享相同的激素环境，但不同的器官可能独立地周期。我们认为，在高等动物中实现生理子系统的昼夜节律协调的一种方法可能是通过环境信号直接夹带光敏时钟。
Circadian rhythms in behaviors and physiological processes are driven by conserved molecular mechanisms involving the rhythmic expression of clock genes in the brains of animals [I], The persistence of Similar molecular rhythms in peripheral tissues in vitro [2,3] suggests that these tissues contain self-sustained circadian clocks that may be linked to rhythmic physiological functions. It is not known how brain and peripheral clocks are organized into a synchronized timing system; however, it has been assumed that peripheral clocks submit to a master clock in the brain. To address this matter we examined the expression of two clock genes, period (per) and timeless (tim), in host and transplanted abdominal organs of Drosophila. We found that excretory organs in tissue culture display free-running, light-sensitive oscillations in per and tim gene activity indicating that they house self-sustained circadian clocks. To test for humoral factors, we monitored cycling of the TIM protein in excretory tubules transplanted into host flies entrained to an opposite light-dark cycle. We show that the clock protein in the donor tubules cycled out of phase with that in the host tubules, indicating that different organs may cycle independently, despite sharing the same hormonal milieu. We suggest that one way to achieve circadian coordination of physiological sub-systems in higher animals may be through the direct entrainment of light sensitive clocks by environmental signals.