The N-Terminal α-Helix of Potato Virus X-Encoded RNA-Dependent RNA Polymerase Is Required for Membrane Association and Multimerization

Positive-sense single-stranded RNA viruses replicate in virus-induced membranous organelles for maximum efficiency and immune escaping. The replication of potato virus X (PVX) takes place on the endoplasmic reticulum (ER); however, how PVX-encoded RNA-dependent RNA polymerase (RdRp) is associated with the ER is still unknown. A proline-kinked amphipathic alpha-helix was recently found in the MET domain of RdRp. In this study, we further illustrate that the first alpha-helix of the MET domain is also required for ER association. Moreover, we found that the MET domain forms multimers on ER and the first alpha-helix is essential for multimerization. These results suggest that the RdRp of PVX adopts more than one hydrophobic motif for membrane association and for multimerization.

Automated summary

This study reveals the association mechanism and multimerization process of RNA-dependent RNA polymerase with endoplasmic reticulum during the replication of potato virus X.