Elsevier

Virology

Volume 247, Issue 1, 20 July 1998, Pages 7-13
Virology

Regular Article
The Carboxy-Terminal p3GagDomain of the Human Foamy Virus Gag Precursor Is Required for Efficient Virus Infectivity

https://doi.org/10.1006/viro.1998.9234Get rights and content
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Abstract

Proteolytic processing of foamy virus Gag proteins appears to be different from that of other retroviruses. A single carboxy-terminal cleavage site is consistently detectable in human foamy virus (HFV) Gag precursor protein p74Gagderived from infected cells and/or purified virus particles. Using a recombinant HFV protease, we have determined the p74Gagcleavage site that results in p70Gagand the carboxy-terminal p3Gag(Pfrepperet al.,1997,Biochem. Biophys. Res. Commun.237, 548–553). To study the biological functions of p3Gag, proviral DNA clones were constructed coding for a carboxy-terminally truncated p70Gaglacking the entire p3Gagprotein. Removal of p3Gagresulted in an about 100-fold lower virus titer. The expression of other HFV proteins and the processing of Pol proteins were indistinguishable from those of wild-type-transfected cells. The defect in viral infectivity of the p3 mutants was partially restored by coexpressing the full-length p74Gagproteinin trans.The deletion of p3Gagresulted in particle assembly with wild-type virion morphology and encapsidation of Pol proteins. Our data show that the carboxy-terminal p3Gagprotein has an important function for viral infectivity but is not required for preassembly of capsids, virus morphogenesis, and incorporation of Pol proteins into virions.

Cited by (0)

B. N. FieldsD. M. KnipeP. M. Howley

1

To whom correspondence and reprint requests should be adressed at Abteilung Retrovirale Genexpression, Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, D - 69009 Heidelberg, Germany. Fax: 49-6221-42-4865. E-mail:[email protected].