Identification of an RNA Silencing Suppressor Encoded by a Symptomless Fungal Hypovirus, Cryphonectria Hypovirus 4.
Identification of an RNA Silencing Suppressor Encoded by a Symptomless Fungal Hypovirus, Cryphonectria Hypovirus 4.
复制标题
DOI：
10.3390/biology10020100
复制
发表时间：
2021-01-31
期刊：
影响因子：
4.2
通讯作者：
Suzuki N
中科院分区：
文献类型：
--
作者：
Aulia A;Hyodo K;Hisano S;Kondo H;Hillman BI;Suzuki N
宿主抗病毒防御/病毒反防御是现代病毒学中一个有趣的话题。RNA沉默是昆虫、植物和真菌中的主要抗病毒机制，而病毒编码并利用RNA沉默抑制子对抗宿主防御。低病毒是正义单链RNA病毒，与小核糖核酸样超群（包括动物脊髓灰质炎病毒和植物马铃薯Y病毒）具有系统发育亲和力。原型hypovirus Cryphonectria hypovirus 1，CHV 1，是研究最多的真菌病毒之一。已知其在栗疫病真菌栗疫病菌（Cryphonectria parasitica）中诱导低毒力，并编码RNA沉默抑制子。CHV 4是另一种无症状感染同一宿主真菌的低病毒。这项研究表明，CHV 4多聚蛋白的N-末端部分，称为p24，是一种蛋白酶，自催化切割本身从病毒多聚蛋白的其余部分，并作为一种抗病毒RNA沉默抑制剂。先前，我们已经报道了栗疫病菌的无菌低病毒Cryphonectria hypovirus 4（CHV 4）促进共感染的呼肠孤病毒2（MyRV 2）的稳定感染的能力-可能是通过CHV 4对RNA沉默的抑制作用（Aulia et al. Virology，2019）。在这项研究中，CHV 4多聚蛋白的N-末端部分，称为p24，被确定为能够抑制宿主抗病毒RNA沉默的自催化蛋白酶。使用细菌表达系统，CHV 4 p24显示出通过其蛋白酶活性在多蛋白的二甘氨酸肽（Gly 214-Gly 215）处自催化切割。CHV 4 p24在栗疫病菌中的转基因表达抑制了抗病毒RNA沉默的关键基因之一dicer-like 2的诱导，并稳定了RNA沉默敏感病毒MyRV 2的感染。这项研究显示了CHV 4 p24和其同源物p29之间的功能相似性，由症状原型hypovirus CHV 1编码。
Host antiviral defense/viral counter-defense is an interesting topic in modern virology. RNA silencing is the primary antiviral mechanism in insects, plants, and fungi, while viruses encode and utilize RNA silencing suppressors against the host defense. Hypoviruses are positive-sense single-stranded RNA viruses with phylogenetic affinity to the picorna-like supergroup, including animal poliovirus and plant potyvirus. The prototype hypovirus Cryphonectria hypovirus 1, CHV1, is one of the best-studied fungal viruses. It is known to induce hypovirulence in the chestnut blight fungus, Cryphonectria parasitica, and encode an RNA silencing suppressor. CHV4 is another hypovirus asymptomatically that infects the same host fungus. This study shows that the N-terminal portion of the CHV4 polyprotein, termed p24, is a protease that autocatalytically cleaves itself from the rest of the viral polyprotein, and functions as an antiviral RNA silencing suppressor. Previously, we have reported the ability of a symptomless hypovirus Cryphonectria hypovirus 4 (CHV4) of the chestnut blight fungus to facilitate stable infection by a co-infecting mycoreovirus 2 (MyRV2)—likely through the inhibitory effect of CHV4 on RNA silencing (Aulia et al., Virology, 2019). In this study, the N-terminal portion of the CHV4 polyprotein, termed p24, is identified as an autocatalytic protease capable of suppressing host antiviral RNA silencing. Using a bacterial expression system, CHV4 p24 is shown to cleave autocatalytically at the di-glycine peptide (Gly214-Gly215) of the polyprotein through its protease activity. Transgenic expression of CHV4 p24 in Cryphonectria parasitica suppresses the induction of one of the key genes of the antiviral RNA silencing, dicer-like 2, and stabilizes the infection of RNA silencing-susceptible virus MyRV2. This study shows functional similarity between CHV4 p24 and its homolog p29, encoded by the symptomatic prototype hypovirus CHV1.
登录
查看更多内容
影响因子：
14.9
作者：
Eusebio-Cope A;Suzuki N
通讯作者：
Suzuki N
影响因子：
6.7
作者：
Campo S;Gilbert KB;Carrington JC
通讯作者：
Carrington JC
影响因子：
3.2
作者：
ENEBAK, SA;MACDONALD, WL;HILLMAN, BI
通讯作者：
HILLMAN, BI
影响因子：
6.4
作者：
Chiba, Sotaro;Jamal, Atif;Suzuki, Nobuhiro
通讯作者：
Suzuki, Nobuhiro
影响因子：
16.6
作者：
Honda S;Eusebio-Cope A;Miyashita S;Yokoyama A;Aulia A;Shahi S;Kondo H;Suzuki N
通讯作者：
Suzuki N