Structural and Biochemical Characterisation of Bunyavirus L proteins.

• Applicant: Dr. Sophia Reindl
• Subject Area: Structural Biology ; Virology
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 262051160

• Final Report Year: 2019

Final Report Abstract

Structural data on the L protein from the virus familiy Bunyaviridae and negative strand RNA viruses in general is very scarce. Besides the N-terminal endonuclease domain all available structural data is from the polymerase complex of influenza (family Orthomyxoviridae) that differs from the L protein by consisting of three separate polypeptide chains instead of one single protein. Sequence homology is very low and structural and functional conservation is only proposed. The goal of this project was to understand the molecular basis of Bunyavirus replication and transcription at atomic resolution to establish a basis for further medical research. The project can be considered as successful as a lot of new insight on the replication and transcription mechanisms could be obtained. The only significant change to the originally proposed project is a broader selection of the viruses studied: we also included several arenaviruses, which are closely related to the bunyaviruses. In the recent year and thanks to many new virus sequences and phylogenetic analyses, the arenaviruses were proposed to not be considered as a family besides the family of bunyaviruses but a family within the new order of Bunyavirales. This recent development shows how closely related those viruses are and justifies our decision to look at the replication and transcription machinery of the whole genus for comparative studies. We determined new structures of subdomains of L proteins and could prove the presence of astonishingly high structural conservation between viruses, although no sequence conservation is present. This is an important step towards the development of broad-spectrum antiviral compounds, as all studied cap-snatching endonucleases could be inhibited by the same molecule the influenza inhibitor DPBA. The generation of high amounts of pure full-length L proteins from different viruses allowed for a detailed characterization of the RNA synthesis mechanism of this large machine. Thereby we obtained new insights into the prime-and-realign mechanism for primer-independent initiation as well as the role of the promoter structure.

Publications

• (2019) Biochemical characterization of the Lassa virus L protein. Journal of Biological Chemistry 294 (20) 8088-8100
  Vogel D, Rosenthal M, Gogrefe N, Reindl S, Günther S
  
• Atomic Structure and Biochemical Characterization of an RNA Endonuclease in the N Terminus of Andes Virus L Protein. PLoS Pathog. 2016 Jun 14;12(6):e1005635
  Fernández-García Y, Reguera J, Busch C, Witte G, Sánchez-Ramos O, Betzel C, Cusack S, Günther S, Reindl S
  
• Structural insights into reptarenavirus cap-snatching machinery. PLoS Pathog. 2017 May 15;13(5):e1006400
  Rosenthal M, Gogrefe N, Vogel D, Reguera J, Rauschenberger B, Cusack S, Günther S, Reindl S
  
• Biochemical and structural studies reveal differences and commonalities among cap-snatching endonucleases from segmented negative-strand RNA viruses. J Biol Chem. 2018 Dec 21;293(51):19686-19698
  Holm T, Kopicki JD, Busch C, Olschewski S, Rosenthal M, Uetrecht C, Günther S, Reindl S