title: Cis-preferential recruitment of duck hepatitis B virus core protein to the RNA/polymerase preassembly complex.
abstract: Hepadnaviral replication requires the concerted action of the polymerase and core proteins to ensure selective packaging of the RNA pregenome into nucleocapsids. Virus assembly is initiated by cis-preferential binding of polymerase to the encapsidation signal straightepsilon, present on pregenomic RNA. Using the duck hepatitis B virus (DHBV) model, we analyzed how core protein is recruited to the RNA/polymerase preassembly complex. Two sets of trans-complementation assays were performed in cotransfected hepatoma cells. First, a replication-competent DHBV construct was tested for its ability to rescue replication of genomes bearing mutations within the core region. Self-packaging of wild-type pregenomes was more efficient than cross-packaging of core-deficient pregenomes, and this bias was strongly enhanced if mutant pregenomes coded for self-assembly-competent, but packaging-deficient, core proteins. Second, the site of wild-type core protein translation, i.e., pregenomic RNA (cis) or separate messenger RNA (trans), was analyzed for its effect on the phenotype of a previously described dominant-negative (DN) DHBV core protein mutant. This mutant forms chimeric nucleocapsids with wild-type core proteins and blocks reverse transcription within most, but not all, mixed particles. Strikingly, suppression of viral DNA synthesis by the mutant increased 100-fold when wild-type core protein was provided in trans. Our results suggest that recruitment of core protein to the DHBV preassembly complex occurs in a cis-preferential manner. This mechanism may account for the leakiness of DN DHBV core protein mutants targeting reverse transcription.
authors.affiliation: Department of Medicine II, University of Freiburg, Freiburg, Germany. weiz@ukl.uni-freiburg.de
authors.forename: Fritz
authors.initials: F
authors.lastname: von Weizsäcker
authors.forename: Josef
authors.initials: J
authors.lastname: Köck
authors.forename: Stefan
authors.initials: S
authors.lastname: Wieland
authors.forename: Jürgen
authors.initials: J
authors.lastname: Beck
authors.forename: Michael
authors.initials: M
authors.lastname: Nassal
authors.forename: Hubert E
authors.initials: HE
authors.lastname: Blum
mesh_terms: D001665:Binding Sites; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D004279:DNA, Viral / Q000096:biosynthesis; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D019281:Dimerization; D015611:Hepatitis B Virus, Duck / Q000737:chemistry* / Q000502:physiology; D009154:Mutation; D019251:Nucleocapsid / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D014158:Transcription, Genetic; D014758:Viral Core Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral; D014758:Viral Core Proteins; D012321:DNA-Directed RNA Polymerases