Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Virol. 2004 Nov;78(21):11751-7.

Translation of duck hepatitis B virus reverse transcriptase by ribosomal shunting.

Author information

  • 1Department of Molecular Microbiology and Immunology, St. Louis University School of Medicine, 1402 S. Grand Blvd., St. Louis, MO 63104, USA.

Abstract

The duck hepatitis B virus (DHBV) polymerase (P) is translated by de novo initiation from a downstream open reading frame (ORF) that partially overlaps the core (C) ORF on the bicistronic pregenomic RNA (pgRNA). The DHBV P AUG is in a poor context for translational initiation and is preceded by 14 AUGs that could intercept scanning ribosomes, yet P translation is unanticipatedly rapid. Therefore, we assessed C and P translation in the context of the pgRNA. Mutating the upstream C ORF revealed that P translation was inversely related to C translation, primarily due to occlusion of P translation by ribosomes translating C. Translation of the pgRNA was found to be cap dependent, because inserting a stem-loop (BamHI-SL) that blocked >90% of scanning ribosomes at the 5' end of the pgRNA greatly inhibited C and P synthesis. Neither mutating AUGs between the C and P start sites in contexts similar to that of the P AUG nor blocking ribosomal scanning by inserting the BamHI-SL between the C and P start codons greatly altered P translation, indicating that most ribosomes that translate P do not scan through these sequences. Finally, optimizing the P AUG context did not increase P translation. Therefore, the majority of the ribosomes that translate P are shunted from a donor region near the 5' end of the pgRNA to an acceptor site at or near the P AUG, and the shunt acceptor sequences may augment initiation at the P AUG.

PMID:
15479816
[PubMed - indexed for MEDLINE]
PMCID:
PMC523253
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk