PMID: 31914382

Authors:

Wang W, Shin WJ, Zhang B, Choi Y, Yoo JS, Zimmerman MI, Frederick TE, Bowman GR, Gross ML, Leung DW, Jung JU, Amarasinghe GK

Title:

The Cap-Snatching SFTSV Endonuclease Domain Is an Antiviral Target.

Journal:

Cell Rep. 2020 Jan 7;30(1):153-163.e5. doi: 10.1016/j.celrep.2019.12.020.

Abstract:

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne virus with 12%-30% case mortality rates and is related to the Heartland virus (HRTV) identified in the United States. Together, SFTSV and HRTV are emerging segmented, negative-sense RNA viral (sNSV) pathogens with potential global health impact. Here, we characterize the amino-terminal cap-snatching endonuclease domain of SFTSV polymerase (L) and solve a 2.4-A X-ray crystal structure. While the overall structure is similar to those of other cap-snatching sNSV endonucleases, differences near the C terminus of the SFTSV endonuclease suggest divergence in regulation. Influenza virus endonuclease inhibitors, including the US Food and Drug Administration (FDA) approved Baloxavir (BXA), inhibit the endonuclease activity in in vitro enzymatic assays and in cell-based studies. BXA displays potent activity with a half maximal inhibitory concentration (IC50) of approximately 100 nM in enzyme inhibition and an EC50 value of approximately 250 nM against SFTSV and HRTV in plaque assays. Together, our data support sNSV endonucleases as an antiviral target.