Coronavirus disease 2019 (COVID-19) has caused massive disruptions to society and the economy, and the transcriptional regulatory mechanisms behind the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are poorly understood. Herein, we determined the crystal structure of the SARS-CoV-2 nucleocapsid protein C-terminal domain (CTD) at a resolution of 2.0 Å, and demonstrated that the CTD has a comparable distinct electrostatic potential surface to equivalent domains of other reported CoVs, suggesting that the CTD has novel roles in viral RNA binding and transcriptional regulation. Further in vitro biochemical assays demonstrated that the viral genomic intergenic transcriptional regulatory sequences (TRSs) interact with the SARS-CoV-2 nucleocapsid protein CTD with a flanking region. The unpaired adeno dinucleotide in the TRS stem-loop structure is a major determining factor for their interactions. Taken together, these results suggested that the nucleocapsid protein CTD is responsible for the discontinuous viral transcription mechanism by recognizing the different patterns of viral TRS during transcription.

2019年冠状病毒病（COVID-19）已对社会和经济造成了巨大破坏，对严重急性呼吸系统综合症冠状病毒2（SARS-CoV-2）背后的转录调控机制知之甚少。在这里，我们以2.0的分辨率确定了SARS-CoV-2核衣壳蛋白C末端域（CTD）的晶体结构，并证明了CTD具有与其他报道的CoV的等效域相当的独特静电势表面，提示CTD在病毒RNA结合和转录调控中具有新作用。进一步体外生化分析表明，病毒基因组间基因转录调控序列（TRS）与SARS-CoV-2核衣壳蛋白CTD的侧翼区域相互作用。TRS茎环结构中未配对的腺二核苷酸是决定其相互作用的主要因素。综上所述，这些结果表明核衣壳蛋白CTD通过识别转录过程中病毒TRS的不同模式来负责不连续的病毒转录机制。