DNA helicase-mediated packaging of adeno-associated virus type 2 genomes into preformed capsids

EMBO J. 2001 Jun 15;20(12):3282-91. doi: 10.1093/emboj/20.12.3282.


Helicases not only catalyse the disruption of hydrogen bonding between complementary regions of nucleic acids, but also move along nucleic acid strands in a polar fashion. Here we show that the Rep52 and Rep40 proteins of adeno-associated virus type 2 (AAV-2) are required to translocate capsid-associated, single-stranded DNA genomes into preformed empty AAV-2 capsids, and that the DNA helicase function of Rep52/40 is essential for this process. Furthermore, DNase protection experiments suggest that insertion of AAV-2 genomes proceeds from the 3' end, which correlates with the 3'-->5' processivity demonstrated for the Rep52/40 helicase. A model is proposed in which capsid-immobilized helicase complexes act as molecular motors to 'pump' single-stranded DNA across the capsid boundary.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Capsid / metabolism*
  • Cell Line, Transformed
  • DNA Helicases / metabolism*
  • DNA, Viral / metabolism
  • DNA-Binding Proteins / metabolism*
  • Dependovirus / genetics
  • Dependovirus / physiology*
  • Genome, Viral*
  • Humans
  • Viral Proteins / metabolism*
  • Virus Assembly / physiology*


  • DNA, Viral
  • DNA-Binding Proteins
  • Viral Proteins
  • rep proteins, Adeno-associated virus 2
  • DNA Helicases