Early gene Broad complex plays a key role in regulating the immune response triggered by ecdysone in the Malpighian tubules of Drosophila melanogaster.
Early gene Broad complex plays a key role in regulating the immune response triggered by ecdysone in the Malpighian tubules of Drosophila melanogaster.
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DOI：
10.1016/j.molimm.2015.03.249
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发表时间：
2015-08
影响因子：
3.6
通讯作者：
P. Verma;M. G. Tapadia
中科院分区：
文献类型：
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作者：
P. Verma;M. G. Tapadia
在昆虫中，体液免疫应答是通过血淋巴分泌抗菌肽（Antimicrobial Peptides，AMPs）来完成的，而果蝇马氏管（DrosophilaMalpighian tubules，MTs）是一种独特的免疫器官，即使在未受攻击的条件下也能组成性表达AMPs，并且免疫应答的发生依赖于发育阶段。早期的报道表明，蜕皮激素积极调节免疫反应后病原体的挑战，然而，一个强大的反应需要事先增强激素。在这里，我们提供的证据表明，MT不需要事先增强蜕皮激素的AMP的表达，他们响应蜕皮激素非常快，即使没有免疫攻击，虽然不同的AMP Diptericin，天蚕素，Attacin，Drosocin显示差异表达响应蜕皮激素。我们表明，早期基因Broad复合物（BR-C）可以通过激活Relish并与其物理相互作用以激活AMP表达来调节IMD途径。马氏管BR-C缺失使果蝇易受感染。我们还表明，在MT蜕皮激素信号转导的EcR-B1和B2。在不存在蜕皮激素信号传导的情况下，IMD途径相关基因被下调，并且转录因子Relish的活化和易位也受到影响。
In insects, humoral response to injury is accomplished by the production of antimicrobial peptides (AMPs) which are secreted in the hemolymph to eliminate the pathogen.DrosophilaMalpighian tubules (MTs), however, are unique immune organs that show constitutive expression of AMPs even in unchallenged conditions and the onset of immune response is developmental stage dependent. Earlier reports have shown ecdysone positively regulates immune response after pathogenic challenge however, a robust response requires prior potentiation by the hormone. Here we provide evidence to show that MTs do not require prior potentiation with ecdysone hormone for expression of AMPs and they respond to ecdysone very fast even without immune challenge, although the different AMPs Diptericin, Cecropin, Attacin, Drosocin show differential expression in response to ecdysone. We show that early gene Broad complex (BR-C) could be regulating the IMD pathway by activating Relish and physically interacting with it to activate AMPs expression. BR-C depletion from Malpighian tubules renders the flies susceptible to infection. We also show that in MTs ecdysone signaling is transduced by EcR-B1 and B2. In the absence of ecdysone signaling the IMD pathway associated genes are down regulated and activation and translocation of transcription factor Relish is also affected.