Abstract
Norovirus (NoV) is a leading cause of epidemic acute non-bacterial gastroenteritis, and replicates through virion protein genome-linked (VPg)-primed or de novo RNA synthesis by RNA-dependent RNA polymerase (RdRp). VPg is a multifunctional protein that plays crucial roles in viral protein translation and genome replication. However, the interaction between the RdRp and this multifunctional VPg in NoV replication has been unknown. In this study, VPg derived from murine NoV (MNV) was found to mediate the formation of higher-order multimers or tubular fibrils of MNV RdRp, which led to significantly enhanced polymerase activity in vitro. The replication of MNV mutants containing a VPg-binding defective RdRp, based on the crystal structure of an RdRp-VPg(1-73) complex, was completely blocked in a cell culture system. Our data suggest that the interaction between RdRp and VPg plays a crucial role in the multimerization-mediated RdRp activity in vivo and consequently in MNV replication, which can provide a new target of therapeutic intervention for NoV outbreaks.
Highlights
Human norovirus (HuNV) is currently a leading cause of acute gastroenteritis in adults and predicted to become the predominant cause of diarrhea in all age groups worldwide (Patel et al, 2008; Bok and Green, 2012)
We initially examined the RNA-dependent RNA polymerase (RdRp)–virion protein genome-linked (VPg) interaction using chemical crosslinking with glutaraldehyde, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting
Protein bands of approximately 76 kDa were detected by both antiRdRp and anti-VPg antisera when VPg was incubated with RdRp, matching the sum of the RdRp (59.7 kDa) and VPg (16.6 kDa) masses
Summary
Human norovirus (HuNV) is currently a leading cause of acute gastroenteritis in adults and predicted to become the predominant cause of diarrhea in all age groups worldwide (Patel et al, 2008; Bok and Green, 2012). The initiation of RNA synthesis by RdRp on an RNA template can be either primer-dependent or -independent in Caliciviridae, Picornaviridae, and Potyviridae (Green, 2007; Goodfellow, 2011; Jiang and Laliberte, 2011). In the former case, VPg serves as a primer for these viruses, providing free hydroxyl groups from a tyrosine or serine residue. The crystal structure of the complex provided the evidence that the interaction between VPg and RdRp plays a crucial role in NoV replication through the higher-order multimer formation of RdRp molecules
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
