Yang Xiaoyao, Zeng Qiurui, Wang Mingshu, Cheng Anchun, Pan Kangcheng, Zhu Dekang, Liu Mafeng, Jia Renyong, Yang Qiao, Wu Ying, Chen Shun, Zhao Xinxin, Zhang Shaqiu, Liu Yunya, Yu Yanling, Zhang Ling
Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, China.
Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.
Front Microbiol. 2018 Nov 15;9:2727. doi: 10.3389/fmicb.2018.02727. eCollection 2018.
Duck hepatitis A virus 1 (DHAV-1) belongs to the genus in the family . Little research has been carried out on the non-structural proteins of this virus. This study reports that 2A1 protein, the first non-structural protein on the DHAV-1 genome, has a ribosomal "skipping" function mediated by a "-GxExNPGP-" motif. In addition, we prove that when the sequence is extended 10aa to VP1 from the N-terminal of 2A1, the ribosome "skips" completely. However, as the N-terminus of 2A is shortened, the efficiency of ribosomal "skipping" reduces. When 2A1 is shortened to 10aa, it does not function. In addition, we demonstrate that N, P G, and P have vital roles in this function. We find that the expression of upstream and downstream proteins linked by 2A1 is different, and the expression of the upstream protein is much greater than that of the downstream protein. In addition, we demonstrate that it is the nature of 2A1 that is responsible for the expression imbalance. We also shows that the protein "cleavage" is not due to RNA "cleavage" or RNA transcription abnormalities, and the expressed protein level is independent of RNA transcriptional level. This study provides a systematic analysis of the activity of the DHAV-1 2A1 sequence and, therefore, adds to the "tool-box" that can be deployed for the co-expression applications. It provides a reference for how to apply 2A1 as a co-expression tool.
鸭甲型肝炎病毒1型（DHAV-1）属于 科中的 属。对该病毒的非结构蛋白研究较少。本研究报道，DHAV-1基因组上的首个非结构蛋白2A1蛋白具有由“-GxExNPGP-”基序介导的核糖体“跳跃”功能。此外，我们证明，当从2A1的N端向VP1延伸10个氨基酸序列时，核糖体完全“跳跃”。然而，随着2A N端缩短，核糖体“跳跃”效率降低。当2A1缩短至10个氨基酸时，其失去功能。此外，我们证明N、P G和P在该功能中起重要作用。我们发现由2A1连接的上下游蛋白的表达不同，且上游蛋白的表达远高于下游蛋白。此外，我们证明是2A1的特性导致了表达失衡。我们还表明，蛋白“切割”并非由于RNA“切割”或RNA转录异常，且表达的蛋白水平与RNA转录水平无关。本研究对DHAV-1 2A1序列的活性进行了系统分析，因此为可用于共表达应用的“工具箱”增添了内容。它为如何将2A1用作共表达工具提供了参考。
