Evolution of the DEAD box helicase family in chicken: chickens have no DHX9 ortholog
Evolution of the DEAD box helicase family in chicken: chickens have no DHX9 ortholog
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DOI：
10.1111/1348-0421.12322
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发表时间：
2015-10
影响因子：
2.6
通讯作者：
Haruko Sato;H. Oshiumi;Hiromi Takaki;H. Hikono;T. Seya
中科院分区：
文献类型：
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作者：
Haruko Sato;H. Oshiumi;Hiromi Takaki;H. Hikono;T. Seya
病毒RNA代表了一种可以被先天免疫中的RNA传感器识别的模式分子。人类和小鼠具有用于检测病毒复制的细胞质DNA/RNA传感器。在哺乳动物中存在许多DEAD（Asp-Glu-Ala-Asp; DExD/H）盒型解旋酶，其中视黄酸诱导基因1（RIG-I）和黑色素瘤分化相关蛋白5（MDA 50）对于RNA传感是不可或缺的;然而，它们在功能上由许多传感器支持，这些传感器直接结合病毒RNA或复制RNA中间体以将信号传递到RIG-I和MDA 5。一些DEAD盒解旋酶成员识别DNA而不管其来源。这些传感器通过接头传递IFN诱导信号，包括线粒体抗病毒信号。据报道，除了RIG-I和MDA 5之外，病毒双链RNA还被解旋酶DDX 1、DDX 21、DHX 36、DHX 9、DDX 3、DDX 41、LGP 2和DDX 60感测，并诱导I型IFN，从而阻断病毒复制。人类和老鼠都有这里列出的所有核酸传感器。在鸡的RNA传感系统中，在本研究中发现大多数DEAD盒解旋酶是保守的;然而，除了报道的RIG-I之外，DHX 9是遗传缺陷的。根据目前的基因组数据库，在鸭子和其他几种鸟类中观察到类似的DHX 9缺乏症。因为发现鸡而不是鸭缺乏RIG-I，所以鸡的RNA传感系统缺乏RIG-I和DHX 9，因此比鸭或哺乳动物更脆弱。DHX 9通常可以补偿RIG-I的功能，并且DHX 9的缺乏可能参与病毒感染的恶化，例如鸡中的流感。
Viral RNA represents a pattern molecule that can be recognized by RNA sensors in innate immunity. Humans and mice possess cytoplasmic DNA/RNA sensors for detecting viral replication. There are a number of DEAD (Asp‐Glu‐Ala‐Asp; DExD/H) box‐type helicases in mammals, among which retinoic acid‐inducible gene 1 (RIG‐I) and melanoma differentiation‐associated protein 5 (MDA50) are indispensable for RNA sensing; however, they are functionally supported by a number of sensors that directly bind viral RNA or replicative RNA intermediates to convey signals to RIG‐I and MDA5. Some DEAD box helicase members recognize DNA irrespective of the origin. These sensors transmit IFN‐inducing signals through adaptors, including mitochondrial antiviral signaling. Viral double‐stranded RNAs are reportedly sensed by the helicases DDX1, DDX21, DHX36, DHX9, DDX3, DDX41, LGP2 and DDX60, in addition to RIG‐I and MDA5, and induce type I IFNs, thereby blocking viral replication. Humans and mice have all nucleic acid sensors listed here. In the RNA sensing system in chicken, it was found in the present study that most DEAD box helicases are conserved; however, DHX9 is genetically deficient in addition to reported RIG‐I. Based on the current genome databases, similar DHX9 deficiency was observed in ducks and several other bird species. Because chicken, but not duck, was found to be deficient in RIG‐I, the RNA‐sensing system of chicken lacks RIG‐I and DHX9 and is thus more fragile than that of duck or mammal. DHX9 may generally compensate for the function of RIG‐I and deficiency of DHX9 possibly participates in exacerbations of viral infection such as influenza in chickens.