RT Journal Article SR Electronic(1) A1 Han, Kang Rok A1 Choi, Yubin A1 Min, Byung Sup A1 Jeong, Hyesook A1 Cheon, Doosung A1 Kim, Jonghyun A1 Jee, Youngmee A1 Shin, Sungho A1 Yang, Jai MyungYR 2010 T1 Murine norovirus-1 3Dpol exhibits RNA-dependent RNA polymerase activity and nucleotidylylates on Tyr of the VPg JF Journal of General Virology, VO 91 IS 7 SP 1713 OP 1722 DO https://doi.org/10.1099/vir.0.020461-0 PB Microbiology Society, SN 1465-2099, AB We investigated the roles and biochemical properties of recombinant murine norovirus-1 (MNV-1) 3Dpol in RNA synthesis and virus genome-linked protein (VPg) nucleotidylylation. We therefore expressed VPg and 3Dpol of MNV-1 in Escherichia coli. MNV-1 3Dpol exhibited RNA-dependent RNA polymerase (RdRp) activity in vitro with poly(A) RNA as a template and MnCl2 as a cofactor. MNV-1 3Dpol demonstrated optimum RNA-synthesis activity at pH 7.4 and 37 °C in the absence of a primer. Further, VPg was guanylylated by MNV-1 3Dpol in the presence of MnCl2 in a template-independent manner. The guanylylation reaction conducted with VPg substitution mutants (Y26F, Y40F, Y45F and Y117F) and a deletion mutant (Δ117–124) indicated that Tyr117 was the probable target site of guanylylation. Homopolymeric RNAs did not enhance VPg guanylylation, whereas in vitro-transcribed (−) subgenomic (SG) and (+)SG RNA enhanced VPg guanylylation by 9.2 and 3.2 times, respectively. Within (−)SG RNA, the (−)ORF3 region played a critical role in enhancing VPg guanylylation, suggesting that the MNV-1 ORF3 region of negative-strand RNA contains a cis-acting element that stimulates 3Dpol-mediated VPg guanylylation., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.020461-0