Institute for Structural and Molecular Biology, University College London, London, United Kingdom.
Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czechia.
J Virol. 2020 Apr 16;94(9). doi: 10.1128/JVI.00119-20.
African swine fever virus (ASFV) causes hemorrhagic fever in domestic pigs, presenting the biggest global threat to animal farming in recorded history. Despite the importance of ASFV, little is known about the mechanisms and regulation of ASFV transcription. Using RNA sequencing methods, we have determined total RNA abundance, transcription start sites, and transcription termination sites at single-nucleotide resolution. This allowed us to characterize DNA consensus motifs of early and late ASFV core promoters, as well as a polythymidylate sequence determinant for transcription termination. Our results demonstrate that ASFV utilizes alternative transcription start sites between early and late stages of infection and that ASFV RNA polymerase (RNAP) undergoes promoter-proximal transcript slippage at 5' ends of transcription units, adding quasitemplated AU- and AUAU-5' extensions to mRNAs. Here, we present the first much-needed genome-wide transcriptome study that provides unique insight into ASFV transcription and serves as a resource to aid future functional analyses of ASFV genes which are essential to combat this devastating disease. African swine fever virus (ASFV) causes incurable and often lethal hemorrhagic fever in domestic pigs. In 2020, ASF presents an acute and global animal health emergency that has the potential to devastate entire national economies as effective vaccines or antiviral drugs are not currently available (according to the Food and Agriculture Organization of the United Nations). With major outbreaks ongoing in Eastern Europe and Asia, urgent action is needed to advance our knowledge about the fundamental biology of ASFV, including the mechanisms and temporal control of gene expression. A thorough understanding of RNAP and transcription factor function, and of the sequence context of their promoter motifs, as well as accurate knowledge of which genes are expressed when and the amino acid sequence of the encoded proteins, is direly needed for the development of antiviral drugs and vaccines.
非洲猪瘟病毒（ASFV）可引起家猪出血性发热，是有记录以来对动物养殖的全球最大威胁。尽管 ASFV 非常重要，但人们对其转录的机制和调控知之甚少。我们使用 RNA 测序方法，以单核苷酸分辨率确定了总 RNA 丰度、转录起始位点和转录终止位点。这使我们能够描述 ASFV 早期和晚期核心启动子的 DNA 共识基序，以及转录终止的聚胸苷酸序列决定因素。我们的研究结果表明，ASFV 在感染的早期和晚期阶段利用了不同的转录起始位点，并且 ASFV RNA 聚合酶（RNAP）在转录单元的 5'端经历了启动子近端转录滑动，在 mRNAs 上添加了准模板 AU-和 AUAU-5'延伸。在这里，我们展示了首次急需的全基因组转录组研究，该研究为 ASFV 转录提供了独特的见解，并为未来 ASFV 基因的功能分析提供了资源，这些基因对于对抗这种毁灭性疾病至关重要。非洲猪瘟病毒（ASFV）可引起家猪不可治愈且常致命的出血性发热。2020 年，ASF 呈现出急性和全球性动物健康紧急情况，如果目前没有有效的疫苗或抗病毒药物，这种疾病有可能摧毁整个国家的经济（根据联合国粮食及农业组织）。东欧和亚洲持续发生重大疫情，需要采取紧急行动来推进我们对 ASFV 基本生物学的认识，包括基因表达的机制和时间控制。深入了解 RNAP 和转录因子的功能，以及它们启动子基序的序列背景，以及准确了解哪些基因何时表达以及编码蛋白质的氨基酸序列，对于开发抗病毒药物和疫苗至关重要。
