title: Novel macula-like virus identified in Bombyx mori cultured cells.
abstract: We identified a novel, 6,513-bp-long RNA, termed Bombyx mori macula-like latent virus (BmMLV) RNA, which abundantly expressed in B. mori cultured BmN cells. BmMLV RNA potentially encodes two proteins, putative RNA replicase and coat protein, which share structural features and sequence similarities with those of a plant RNA virus, the genus Maculavirus. Northern blot analysis showed that two transcripts were expressed in BmN cells: a 6.5-kb-long RNA, which contains both putative RNA replicase and coat protein genes, and a 1.2-kb-long RNA, which contains only a coat protein gene. Southern blot analysis showed that BmMLV RNA is not carried by the B. mori genome. RT-PCR analysis also revealed the presence of BmMLV RNA in several B. mori cell lines other than BmN cells, suggesting that BmMLV RNA latently exists in B. mori cultured cells. Infection studies showed that BmMLV virions were able to infect BmMLV-negative Spodoptera frugiperda Sf-9 cells and B. mori larvae. Electron microscopy and Northern blot analysis of a purified BmMLV revealed that isometric virions appear to be 28 to 30 nm in diameter and contain a 6.5-kb genomic RNA. These results showed that BmMLV is a novel macula-like virus infectious to and replicable in B. mori-derived cells.
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Katsuma
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Tanaka
authors.forename: Naoko
authors.initials: N
authors.lastname: Omuro
authors.forename: Lisa
authors.initials: L
authors.lastname: Takabuchi
authors.forename: Takaaki
authors.initials: T
authors.lastname: Daimon
authors.forename: Shigeo
authors.initials: S
authors.lastname: Imanishi
authors.forename: Shuichi
authors.initials: S
authors.lastname: Yamashita
authors.forename: Masashi
authors.initials: M
authors.lastname: Iwanaga
authors.forename: Kazuei
authors.initials: K
authors.lastname: Mita
authors.forename: Susumu
authors.initials: S
authors.lastname: Maeda
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Toru
authors.initials: T
authors.lastname: Shimada
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000254:growth & development / Q000821:virology*; D036022:Capsid Proteins / Q000235:genetics; D002478:Cells, Cultured; D005260:Female; D007814:Larva; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D016415:Sequence Alignment; D046830:Tymoviridae / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D036022:Capsid Proteins; D012367:RNA, Viral; D012324:RNA-Dependent RNA Polymerase