Molecular basis for the formation of ribonucleoprotein complex of Crimean-Congo hemorrhagic fever virus.
Negative-sense single-strand RNA (-ssRNA) viruses comprise a large family of pathogens that cause severe human infectious diseases. All -ssRNA viruses encode a nucleocapsid protein (NP) to encapsidate the viral genome, which, together with polymerase, forms a ribonucleoprotein complex (RNP) that is packaged into virions and acts as the template for viral replication and transcription. In our previous work, we solved the monomeric structure of NP encoded by Crimean-Congo hemorrhagic fever virus (CCHFV), which belongs to the Nairovirus genus within the Bunyaviridae family, and revealed its unusual endonuclease activity. However, the mechanism of CCHFV RNP formation remains unclear, due to the difficulty in reconstructing the oligomeric CCHFV NP-RNA complex. Here, we identified and isolated the oligomeric CCHFV NP-RNA complex that formed in expression cells. Sequencing of RNA extracted from the complex revealed sequence specificity and suggested a potential encapsidation signal facilitating the association between NP and viral genome. A cryo-EM reconstruction revealed the ring-shaped architecture of the CCHFV NP-RNA oligomer, thus defining the interaction between the head and stalk domains that results in NP multimerization. This structure also suggested a modified gating mechanism for viral genome encapsidation, in which both the head and stalk domains participate in RNA binding. This work provides insight into the distinct mechanism underlying CCHFV RNP formation compared to other -ssRNA viruses.
State Key Laboratory of Biomembrane, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
Xiaojing
X
Wang
School of Medicine and MOE Laboratory of Protein Science, Tsinghua University, Beijing 100084, China; School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA.
Baobin
B
Li
College of Pharmacy and State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China; National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China.
Yu
Y
Guo
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Shu
S
Shen
State Key Laboratory of Biomembrane, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
Liang
L
Zhao
School of Medicine and MOE Laboratory of Protein Science, Tsinghua University, Beijing 100084, China.
Peisheng
P
Zhang
National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China.
Yuna
Y
Sun
State Key Laboratory of Biomembrane, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China. Electronic address: suisf@mail.tsinghua.edu.cn.
Sen-Fang
SF
Sui
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China. Electronic address: df@wh.iov.cn.
Fei
F
Deng
School of Medicine and MOE Laboratory of Protein Science, Tsinghua University, Beijing 100084, China; College of Pharmacy and State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China; State Key Laboratory of Biotherapy and Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China. Electronic address: louzy@mail.tsinghua.edu.cn.
Zhiyong
Z
Lou
D018360:Crystallography, X-Ray; D016679:Genome, Viral; D003225:Hemorrhagic Fever Virus, Crimean-Congo / Q000737:chemistry* / Q000235:genetics / Q000472:pathogenicity; D006801:Humans; D008958:Models, Molecular; D019590:Nucleocapsid Proteins / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D012367:RNA, Viral / Q000737:chemistry*; D012261:Ribonucleoproteins / Q000737:chemistry* / Q000235:genetics
D019590:Nucleocapsid Proteins; D012367:RNA, Viral; D012261:Ribonucleoproteins
Architecture; CCHFV; Nucleocapsid protein; Oligomer