Circularization of an RNA template via long-range base pairing is critical for hepadnaviral reverse transcription

Virology. 2008 Feb 20;371(2):362-73. doi: 10.1016/j.virol.2007.09.042. Epub 2007 Nov 7.

Abstract

Although an overall genetic strategy for hepadnaviral reverse transcription has been established, the mechanism that underlies the minus-strand transfer is still poorly defined. We and others independently identified a novel cis-acting element, termed beta or varphi, respectively, that is critical for the minus-strand DNA synthesis of hepatitis B virus. A 5'-3', long-range interaction of the RNA template was proposed that involves the 5' epsilon sequence (encapsidation signal) and the 3' beta/varphi sequence. We subjected the hypothesized base pairing to genetic analysis. The data indicated that mutations abrogating the hypothesized base pairing markedly impaired minus-strand DNA synthesis, while compensatory mutations that restored the base pairing rescued the minus-strand DNA synthesis. These results demonstrated the critical role of the 5'-3', long-range interaction in minus-strand DNA synthesis. We speculate that such a long-range interaction may precisely juxtapose a donor to an acceptor during minus-strand transfer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Pairing*
  • Base Sequence
  • Cell Line, Tumor
  • DNA, Circular / biosynthesis
  • DNA, Viral / biosynthesis*
  • Hepatitis B virus / genetics*
  • Hepatitis B virus / metabolism
  • Humans
  • Molecular Sequence Data
  • Mutation
  • RNA, Viral / genetics*
  • Reverse Transcription*
  • Templates, Genetic*

Substances

  • DNA, Circular
  • DNA, Viral
  • RNA, Viral