Humidity Sensing in Drosophila.
Humidity Sensing in Drosophila.
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DOI：
10.1016/j.cub.2016.03.049
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发表时间：
2016-05-23
期刊：
影响因子：
--
通讯作者：
Stensmyr MC
中科院分区：
文献类型：
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作者：
Enjin A;Zaharieva EE;Frank DD;Mansourian S;Suh GS;Gallio M;Stensmyr MC
环境湿度影响所有动物的健康状况和地理分布。昆虫尤其使用湿度线索来导航环境，以前的工作表明，存在特定的感官机制来检测有利的湿度范围。然而，湿度感应(湿感)的分子和细胞基础仍然知之甚少。在这里，我们描述了醋蝇黑腹果蝇湿感所必需的基因和神经元。我们发现，果蝇属的成员表现出与其原生栖息地的条件有关的物种特有的湿度偏好。通过简单的行为学分析，我们发现趋电性受体IR40a、IR93a和IR25a都是黑腹毛虫湿度偏好所必需的。然而，虽然IR40a是选择性地需要湿感反应，但IR93a和IR25a同时调节湿度和温度偏好。与此相一致的是，IR93a和IR25a的表达包括了Arista的热敏神经元。相反，Ir40a被排除在Arista之外，但在支配球囊无孔感受器的特殊神经元中表达(也是必需的)，球囊感受器是第三触角节段的独特内陷。事实上，钙成像显示，Ir40a神经元直接对湿度变化做出反应，而Ir40a基因敲除或IR93a突变降低了它们对刺激的反应。综上所述，我们的结果表明，对特定湿度范围的偏好取决于特殊的球囊神经元，环境湿度的处理在很大程度上可以与温度的处理平行进行。果蝇喜欢不同的湿度范围，这与它们的栖息地有关。RH偏好都需要IR25a、IR93a和Ir40a的电离子受体，RH的变化由球囊中的Ir40a神经元感知，触角亚结构RH和温度由果蝇触角中的不同细胞处理
Environmental humidity influences the fitness and geographic distribution of all animals. Insects in particular use humidity cues to navigate the environment, and previous work suggests the existence of specific sensory mechanisms to detect favorable humidity ranges. Yet, the molecular and cellular basis of humidity sensing (hygrosensation) remains poorly understood. Here, we describe genes and neurons necessary for hygrosensation in the vinegar fly Drosophila melanogaster. We find that members of the Drosophila genus display species-specific humidity preferences related to conditions in their native habitats. Using a simple behavioral assay, we find that the ionotropic receptors IR40a, IR93a and IR25a are all required for humidity preference in D. melanogaster. Yet, while IR40a is selectively required for hygrosensory responses, IR93a and IR25a mediate both humidity and temperature preference. Consistent with this, the expression of IR93a and IR25a includes thermosensory neurons of the arista. In contrast, IR40a is excluded from the arista, but expressed (and required) in specialized neurons innervating pore-less sensilla of the sacculus, a unique invagination of the third antennal segment. Indeed, calcium imaging shows that IR40a neurons directly respond to changes in humidity, and IR40a knockdown or IR93a mutation reduced their responses to stimuli. Taken together, our results suggest that the preference for a specific humidity range depends on specialized sacculus neurons, and that the processing of environmental humidity can happen largely in parallel to that of temperature. Drosophila species prefer distinct humidity ranges, related to their native habitat The Ionotropic Receptors IR25a, IR93a and IR40a are all required for RH preference RH changes are sensed by Ir40a neurons in the sacculus, an antennal substructure RH and temperature are processed by different cells in the Drosophila antenna