Formation of a functional hepatitis B virus replication initiation complex involves a major structural alteration in the RNA template.
The DNA genome of a hepatitis B virus is generated by reverse transcription of the RNA pregenome. Replication initiation does not involve a nucleic acid primer; instead, the hepadnavirus P protein binds to the structured RNA encapsidation signal epsilon, from which it copies a short DNA primer that becomes covalently linked to the enzyme. Using in vitro-translated duck hepatitis B virus (DHBV) P protein, we probed the secondary structure of the protein-bound DHBV epsilon RNA (Depsilon) and observed a marked conformational change compared to free Depsilon RNA. Several initiation-competent mutant RNAs with a different free-state structure were similarly altered, whereas a binding-competent but initiation-deficient variant was not, indicating the importance of the rearrangement for replication initiation and suggesting a mechanistic coupling to encapsidation.
Beck
J
J
Department of Internal Medicine II/Molecular Biology, University Hospital Freiburg, D-79106 Freiburg, Germany.
Nassal
M
M
D001483:Base Sequence; D004261:DNA Replication / Q000235:genetics*; D015684:Gene Products, pol / Q000378:metabolism; D015611:Hepatitis B Virus, Duck / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000737:chemistry*; D016601:RNA-Binding Proteins / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry; D014764:Viral Proteins / Q000378:metabolism
D015684:Gene Products, pol; C066027:P protein, Hepatitis B virus; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D014764:Viral Proteins; D012194:RNA-Directed DNA Polymerase