title: RNA editing of hepatitis delta virus antigenome by dsRNA-adenosine deaminase.
abstract: Hepatitis delta virus (HDV) is a subviral human pathogen that requires hepatitis B virus (HBV) for packaging. Concurrent infection by HBV and HDV increases the risk of severe liver disease compared to infection with HBV alone. The HDV genome is a closed circular RNA of about 1,700 bases which is replicated through an RNA intermediate, the antigenome. Both RNAs can be folded into highly base-paired, rod-shaped structures, similar to the plant viroid RNAs. Two forms of the sole HDV protein, hepatitis delta antigen, are derived from a single open reading frame by RNA editing; the enzymes responsible for the editing have not been characterized. Here we report that the purified enzyme dsRAD (for double-stranded-RNA-adenosine deaminase) can edit HDV antigenomic RNA in vitro. Most important, we observe that mutations in critical sequences of the antigenome have identical effects on in vitro and in vivo editing, suggesting that dsRAD, or a closely related enzyme, is responsible for editing HDV RNA in vivo.
authors.affiliation: Department of Biochemistry and Howard Hughes Medical Institute, University of Utah, Salt Lake City, 84112, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Polson
authors.forename: B L
authors.initials: BL
authors.lastname: Bass
authors.forename: J L
authors.initials: JL
authors.lastname: Casey
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000243:Adenosine Deaminase / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003641:Deamination; D003698:Hepatitis Delta Virus / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007288:Inosine / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D017393:RNA Editing; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins; D014982:Xenopus laevis
chemical_list: D012367:RNA, Viral; D016601:RNA-Binding Proteins; D007288:Inosine; C567955:ADARB1 protein, human; D000243:Adenosine Deaminase; D000241:Adenosine