Ecdysone signaling is required for proper organization and fluid secretion of stellate cells in the Malpighian tubules of Drosophila melanogaster
Ecdysone signaling is required for proper organization and fluid secretion of stellate cells in the Malpighian tubules of Drosophila melanogaster
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DOI：
10.1387/ijdb.092910ng
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发表时间：
2010-01-01
影响因子：
0.7
通讯作者：
Tapadia, Madhu G.
中科院分区：
文献类型：
--
作者：
Gautam, Naveen-Kumar;Tapadia, Madhu G.
果蝇的发育是一个受严格调控的过程，涉及由相对较少移动的幼虫向高度能动的成虫的变态，由20-羟基蜕皮激素的分泌触发。在蜕皮激素的作用下，幼虫的大部分组织退化，而成虫细胞分化形成成虫特有的结构。虽然幼虫马氏管似乎不受蜕皮激素在变态过程中，我们表明，蜕皮激素信号在马氏管的早期发育和功能发挥着重要作用。使用星状细胞中显性负性蜕皮激素受体的靶向表达来破坏蜕皮激素受体功能，导致马氏管组织的破坏。马氏管中星状细胞的数量减少。此外，它们聚集在一起，而不是以其特有的野生型模式分布。我们还表明，表达果蝇整合素蛋白（DRIP），水通道蛋白负责跨细胞水运输，也减少了星状细胞蜕皮激素信号被破坏时。我们的研究结果表明，三个蜕皮激素受体亚型，只有EcR-B2拯救这些表型。在非允许条件下，在ecd（1）（一种温度敏感突变体）中观察到类似的星状细胞聚集模式和DRIP表达减少。这些结果表明，蜕皮激素信号所需的适当的图案和功能的星状细胞和EcR-B2可能是所需的蜕皮激素信号在星状细胞的主要亚型。
Drosophila development is a tightly regulated process involving metamorphosis of a relatively less mobile larva to a highly motile adult, triggered by secretion of 20-hydroxyecdysone. Under the influence of ecdysone, most of the larval tissues degenerate, while the imaginal cells differentiate and form adult specific structures. Although the larval Malpighian tubules do not seem to be affected by ecdysone during metamorphosis, we show that ecdysone signaling plays an important role in the early development and functioning of Malpighian tubules. Disruption of ecdysone receptor function, using targeted expression of dominant negative ecdysone receptor in stellate cells, results in disruption of organization of Malpighian tubules. The number of stellate cells is reduced in such Malpighian tubules. Further, they get clustered rather than distributed in their characteristic wild type pattern. We also demonstrate that expression of Drosophila integrin protein (DRIP), an aquaporin responsible for trans-cellular water transport, is also reduced in stellate cells when ecdysone signaling is disrupted. Our results show that of the three ecdysone receptor isoforms, only EcR-B2 rescues these phenotypes. A similar pattern of stellate cell clustering and reduced expression of DRIP is observed in ecd(1), a temperature sensitive mutant, under non-permissive conditions. These results suggest that ecdysone signaling is required for proper patterning and functioning of stellate cells and that EcR-B2 may be the primary isoform required for ecdysone signaling in stellate cells.