title: Biochemical and genetic characterization of dengue virus methyltransferase.
abstract: We report that dengue virus (DENV) methyltransferase sequentially methylates the guanine N-7 and ribose 2'-O positions of viral RNA cap (GpppA-->m(7)GpppA-->m(7)GpppAm). The order of two methylations is determined by the preference of 2'-O methylation for substrate m(7)GpppA-RNA to GpppA-RNA, and the 2'-O methylation is not absolutely dependent on the prior N-7 methylation. A mutation that completely abolished the 2'-O methylation attenuated DENV replication in cell culture, whereas another mutation that abolished both methylations was lethal for viral replication, suggesting that N-7 methylation is more important than 2'-O methylation in viral replication. The latter mutant with lethal replication could be rescued by trans complementation using a wild-type DENV replicon. Furthermore, we found that chimeric DENVs containing the West Nile virus methyltransferase, polymerase, or full-length NS5 were nonreplicative, but the replication defect could also be rescued through trans complementation using the wild-type DENV replicon.
authors.affiliation: Novartis Institute for Tropical Diseases, Chromos, Singapore 138670, Singapore. hongping.dong@novartis.com
authors.forename: Hongping
authors.initials: H
authors.lastname: Dong
authors.forename: David C
authors.initials: DC
authors.lastname: Chang
authors.forename: Xuping
authors.initials: X
authors.lastname: Xie
authors.forename: Ying Xiu
authors.initials: YX
authors.lastname: Toh
authors.forename: Ka Yan
authors.initials: KY
authors.lastname: Chung
authors.forename: Gang
authors.initials: G
authors.lastname: Zou
authors.forename: Julien
authors.initials: J
authors.lastname: Lescar
authors.forename: Siew Pheng
authors.initials: SP
authors.lastname: Lim
authors.forename: Pei-Yong
authors.initials: PY
authors.lastname: Shi
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003716:Dengue Virus / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D008745:Methylation; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D012315:RNA Caps / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
chemical_list: D012315:RNA Caps; D012367:RNA, Viral; D014764:Viral Proteins; D008780:Methyltransferases