title: A SELEX-screened aptamer of human hepatitis B virus RNA encapsidation signal suppresses viral replication.
abstract: BACKGROUND
  The specific interaction between hepatitis B virus (HBV) polymerase (P protein) and the ε RNA stem-loop on pregenomic (pg) RNA is crucial for viral replication. It triggers both pgRNA packaging and reverse transcription and thus represents an attractive antiviral target. RNA decoys mimicking ε in P protein binding but not supporting replication might represent novel HBV inhibitors. However, because generation of recombinant enzymatically active HBV polymerase is notoriously difficult, such decoys have as yet not been identified.
  
  
  RESULTS
  Here we used a SELEX approach, based on a new in vitro reconstitution system exploiting a recombinant truncated HBV P protein (miniP), to identify potential ε decoys in two large ε RNA pools with randomized upper stem. Selection of strongly P protein binding RNAs correlated with an unexpected strong enrichment of A residues. Two aptamers, S6 and S9, displayed particularly high affinity and specificity for miniP in vitro, yet did not support viral replication when part of a complete HBV genome. Introducing S9 RNA into transiently HBV producing HepG2 cells strongly suppressed pgRNA packaging and DNA synthesis, indicating the S9 RNA can indeed act as an ε decoy that competitively inhibits P protein binding to the authentic ε signal on pgRNA.
  
  
  CONCLUSIONS
  This study demonstrates the first successful identification of human HBV ε aptamers by an in vitro SELEX approach. Effective suppression of HBV replication by the S9 aptamer provides proof-of-principle for the ability of ε decoy RNAs to interfere with viral P-ε complex formation and suggests that S9-like RNAs may further be developed into useful therapeutics against chronic hepatitis B.
authors: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors: Hui
authors: H
authors: Feng
authors: Jürgen
authors: J
authors: Beck
authors: Michael
authors: M
authors: Nassal
authors: Kang-Hong
authors: KH
authors: Hu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001667:Binding, Competitive; D002470:Cell Survival / Q000235:genetics; D015684:Gene Products, pol / Q000235:genetics / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D019251:Nucleocapsid / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D052156:SELEX Aptamer Technique / Q000379:methods*; D014162:Transfection; D014779:Virus Replication
chemical_list: D052157:Aptamers, Nucleotide; D015684:Gene Products, pol; C066027:P protein, Hepatitis B virus