DNA helicase-mediated packaging of adeno-associated virus type 2 genomes into preformed capsids.
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.
King
J A
JA
Applied Tumour Virology Program, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, D-69120 Heidelberg, Germany.
Dubielzig
R
R
Grimm
D
D
Kleinschmidt
J A
JA
D002213:Capsid / Q000378:metabolism*; D002461:Cell Line, Transformed; D004265:DNA Helicases / Q000378:metabolism*; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D000229:Dependovirus / Q000235:genetics / Q000502:physiology*; D016679:Genome, Viral; D006801:Humans; D014764:Viral Proteins / Q000378:metabolism*; D019065:Virus Assembly / Q000502:physiology*
D004279:DNA, Viral; D004268:DNA-Binding Proteins; D014764:Viral Proteins; C068734:rep proteins, Adeno-associated virus 2; D004265:DNA Helicases