Parvovirus uncoating in vitro reveals a mechanism of DNA release without capsid disassembly and striking differences in encapsidated DNA stability

Ros, Carlos; Baltzer, Claudia; Mani, Bernhard; Kempf, Christoph (2006). Parvovirus uncoating in vitro reveals a mechanism of DNA release without capsid disassembly and striking differences in encapsidated DNA stability. Virology, 345(1), pp. 137-147. New York, N.Y.: Academic Press 10.1016/j.virol.2005.09.030

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The uncoating mechanism of parvoviruses is unknown. Their capsid robustness and increasing experimental data would suggest an uncoating mechanism without capsid disassembly. We have developed an in vitro system to detect and quantify viral DNA externalization and applied the assay on two parvoviruses with important differences in capsid structure, human B19 and minute virus of mice (MVM). Upon briefly treating the capsids to increasing temperatures, the viral genome became accessible in its full-length in a growing proportion of virions. Capsid disassembly started at temperatures above 60 degrees C for B19 and 70 degrees C for MVM. For both viruses, the externalization followed an all-or-nothing mechanism, without transitions exposing only a particular genomic region. However, the heat-induced DNA accessibility was remarkably more pronounced in B19 than in MVM. This difference was also evident under conditions mimicking endosomal acidification (pH 6.5 to 5), which triggered the externalization of B19-DNA but not of MVM-DNA. The externalized ssDNA was a suitable template for the full second-strand synthesis. Immunoprecipitation with antibodies against conformational epitopes and quantitative PCR revealed that the DNA externalized by heat was mostly dissociated from its capsid, however, the low pH-induced DNA externalization of B19 was predominantly capsid-associated. These results provide new insights into parvovirus uncoating suggesting a mechanism by which the full-length viral genome is released without capsid disassembly. The remarkable instability of the encapsidated B19 DNA, which is easily released from its capsid, would also explain the faster heat inactivation of B19 when compared to other parvoviruses.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Ros Bascunana, Carlos, Mani, Bernhard, Kempf, Christoph (B)

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

0042-6822

Publisher:

Academic Press

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:44

Last Modified:

29 Mar 2023 23:32

Publisher DOI:

10.1016/j.virol.2005.09.030

PubMed ID:

16242744

Web of Science ID:

000235117000014

BORIS DOI:

10.48350/18262

URI:

https://boris.unibe.ch/id/eprint/18262 (FactScience: 133)

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