Defective interfering RNA hinders the activity of a tombusvirus-encoded posttranscriptional gene silencing suppressor
Defective interfering RNA hinders the activity of a tombusvirus-encoded posttranscriptional gene silencing suppressor
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DOI：
10.1128/jvi.79.1.450-457.2005
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发表时间：
2005-01-01
影响因子：
5.4
通讯作者：
Burgyán, J
中科院分区：
文献类型：
--
作者：
Havelda, Z;Hornyik, C;Burgyán, J
缺陷性干扰（DI）RNA是源自病毒基因组的亚病毒复制子，并且与许多植物RNA病毒和几乎所有动物RNA病毒相关。在番茄丛矮病毒感染的植物中，DI RNA的存在减少了辅助病毒RNA的积累，并导致与转录后基因沉默（PTGS）抑制子p19缺陷的番茄丛矮病毒引起的症状类似的减弱症状的发展。含有DI RNA的感染植物的原位分析表明，病毒感染的程度是空间上的限制，被发现为p19缺陷的番茄丛矮病毒。以前，p19被证明通过隔离小干扰RNA（siRNA）来抑制PTGS，小干扰RNA作为PTGS的特异性决定因素。我们的研究结果表明，DI RNA显着提高病毒感染中病毒特异性siRNA的水平，导致p19的饱和和未结合siRNA的积累。此外，我们表明，在低温下，其中PTGS被抑制，DI RNA不能有效地干扰病毒积累和保护植物。这些数据表明PTGS的激活在DRNA介导的干扰中起关键作用。我们的数据也支持21个核苷酸的siRNA在PTGS信号传导中的作用。
Defective interfering (DI) RNAs are subviral replicons originating from the viral genome and are associated with many plant RNA viruses and nearly all animal RNA viruses. The presence of DI RNAs in tombusvirus-infected plants reduces the accumulation of helper virus RNA and results in the development of attenuated symptoms similar to those caused by tombusviruses defective in p19, the posttranscriptional gene silencing (PTGS) suppressor. In situ analysis of infected plants containing DI RNAs revealed that the extent of virus infection was spatially restricted as was found for p19-defective tombusvirus. Previously, p19 was shown to suppress PTGS by sequestering the small interfering RNAs (siRNAs), which act as the specificity determinant for PTGS. Our results demonstrate that DI RNAs dramatically elevate the level of virus-specific siRNAs in viral infections, resulting in the saturation of p19 and the accumulation of unbound siRNAs. Moreover, we showed that, at low temperature, where PTGS is inhibited, DI RNAs are not able to efficiently interfere with virus accumulation and protect the plants. These data show that the activation of PTGS plays a pivotal role in DI RNA-mediated interference. Our data also support a role for 21-nucleotide siRNAs in PTGS signaling.