Subtotal spleen necrosis

Activation of the murine leukaemia virus (MLV) envelope protein (Env) requires proteolytic cleavage of the R-peptide, a 16 amino acid C-terminal part of the cytoplasmic tail (C-tail) of Env. This paper demonstrates the presence of R-peptides in Env proteins of C-type retroviruses of simian, avian and porcine origin. Sequence alignment with the MLV C-tail led to the identification of a conserved hydrophobic protease cleavage motif located in the centre of retroviral Env protein C-tails. Expression of Env proteins, truncated at the predicted cleavage sites, of spleen necrosis virus (SNV), gibbon ape leukaemia virus and porcine endogenous retroviruses resulted in cell–cell fusion as monitored by microscopy and reporter gene fusion assays. Western blot analysis of MLV particles pseudotyped with the SNV Env protein demonstrated proteolytic cleavage of the SNV R-peptide by the MLV protease. Our data suggest that activation of membrane fusion by R-peptide cleavage is a common mode in C-type retroviruses.

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Spliced Spleen Necrosis Virus Vector RNA Is Not Encapsidated: Implications for Retroviral Replication and Vector Design

Molecular Therapy ◽

10.1016/j.ymthe.2004.01.009 ◽

2004 ◽

Vol 9 (4) ◽

pp. 557-565 ◽

Cited By ~ 2

Author(s):

Adrienne Goodrich ◽

Zahida Parveen ◽

Ralph Dornburg ◽

Matthias J Schnell ◽

Roger J Pomerantz

Keyword(s):

Virus Vector ◽

Necrosis Virus ◽

Spleen Necrosis Virus ◽

Retroviral Replication ◽

Spleen Necrosis

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Establishment of infection by spleen necrosis virus: inhibition in stationary cells and the role of secondary infection.

Journal of Virology ◽

10.1128/jvi.41.1.183-191.1982 ◽

1982 ◽

Vol 41 (1) ◽

pp. 183-191 ◽

Cited By ~ 23

Author(s):

I S Chen ◽

H M Temin

Keyword(s):

Secondary Infection ◽

Necrosis Virus ◽

Virus Inhibition ◽

Spleen Necrosis Virus ◽

Spleen Necrosis

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The Nucleocapsid Domain Is Responsible for the Ability of Spleen Necrosis Virus (SNV) Gag Polyprotein To Package both SNV and Murine Leukemia Virus RNA

Journal of Virology ◽

10.1128/jvi.73.11.9170-9177.1999 ◽

1999 ◽

Vol 73 (11) ◽

pp. 9170-9177 ◽

Cited By ~ 17

Author(s):

Jeanine L. Certo ◽

Timur O. Kabdulov ◽

Michelle L. Paulson ◽

Jeffrey A. Anderson ◽

Wei-Shau Hu

Keyword(s):

Murine Leukemia Virus ◽

Viral Vector ◽

Leukemia Virus ◽

Gene Products ◽

Rna Packaging ◽

Packaging Signal ◽

Necrosis Virus ◽

Spleen Necrosis Virus ◽

Spleen Necrosis ◽

Murine Leukemia

ABSTRACT Murine leukemia virus (MLV)-based vector RNA can be packaged and propagated by the proteins of spleen necrosis virus (SNV). We recently demonstrated that MLV proteins cannot support the replication of an SNV-based vector; RNA analysis revealed that MLV proteins cannot efficiently package SNV-based vector RNA. The domain in Gag responsible for the specificity of RNA packaging was identified using chimericgag-pol expression constructs. A competitive packaging system was established by generating a cell line that expresses one viral vector RNA containing the MLV packaging signal (Ψ) and another viral vector RNA containing the SNV packaging signal (E). The chimericgag-pol expression constructs were introduced into the cells, and vector titers as well as the efficiency of RNA packaging were examined. Our data confirm that Gag is solely responsible for the selection of viral RNAs. Furthermore, the nucleocapsid (NC) domain in the SNV Gag is responsible for its ability to interact with both SNV E and MLV Ψ. Replacement of the SNV NC with the MLV NC generated a chimeric Gag that could not package SNV RNA but retained its ability to package MLV RNA. A construct expressing SNV gag-MLVpol supported the replication of both MLV and SNV vectors, indicating that the gag and pol gene products from two different viruses can functionally cooperate to perform one cycle of retroviral replication. Viral titer data indicated that SNVcis-acting elements are not ideal substrates for MLVpol gene products since infectious viruses were generated at a lower efficiency. These results indicate that the nonreciprocal recognition between SNV and MLV extends beyond the Gag-RNA interaction and also includes interactions between Pol and othercis-acting elements.

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