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Author Notes:

Email: Andrei N Vzorov* - avzorov@emory.edu

Author ANV designed experiments, carried out most the experiments and wrote the manuscript.

Author AW carried out most experiments for the lipid raft section and drafted this section.

NLK assisted in RT-PCR experiments.

VK and BY carried out microarray analysis.

RWC suggested experiments and revised the manuscript.

The authors thank Dahnide Taylor for technical assistance and Erin-Joi Collins for assistance in preparing the manuscript.

Subjects:

Research Funding:

This study was supported by NIH grants AI028147 and AI45883 from the National Institute of Allergy and Infectious Diseases and Emory CFAR grant (P30 AI050409) for using real-time PCR instruments.

A.W. was supported by a fellowship from the Bundesministerium für Bildung und Forschung, Germany (BMBF-LPD 9901/8-29).

Role of the long cytoplasmic domain of the SIV Env glycoprotein in early and late stages of infection

Tools:

Journal Title:

Retrovirology

Volume:

Volume 4

Publisher:

, Pages 94-94

Type of Work:

Article | Final Publisher PDF

Abstract:

Background The Env glycoproteins of retroviruses play an important role in the initial steps of infection involving the binding to cell surface receptors and entry by membrane fusion. The Env glycoprotein also plays an important role in viral assembly at a late step of infection. Although the Env glycoprotein interacts with viral matrix proteins and cellular proteins associated with lipid rafts, its possible role during the early replication events remains unclear. Truncation of the cytoplasmic tail (CT) of the Env glycoprotein is acquired by SIV in the course of adaptation to human cells, and is known to be a determinant of SIV pathogenicity. Results We compared SIV viruses with full length or truncated (T) Env glycoproteins to analyze possible differences in entry and post-entry events, and assembly of virions. We observed that early steps in replication of SIV with full length or T Env were similar in dividing and non-dividing cells. However, the proviral DNA of the pathogenic virus clone SIVmac239 with full length Env was imported to the nucleus about 20-fold more efficiently than proviral DNA of SIVmac239T with T Env, and 100-fold more efficiently than an SIVmac18T variant with a single mutation A239T in the SU subunit and with a truncated cytoplasmic tail (CT). In contrast, proviral DNA of SIVmac18 with a full length CT and with a single mutation A239T in the SU subunit was imported to the nucleus about 50-fold more efficiently than SIVmac18T. SIV particles with full length Env were released from rhesus monkey PBMC, whereas a restriction of release of virus particles was observed from human 293T, CEMx174, HUT78 or macrophages. In contrast, SIV with T Envs were able to overcome the inhibition of release in human HUT78, CEMx174, 293T or growth-arrested CEMx174 cells and macrophages resulting in production of infectious particles. We found that the long CT of the Env glycoprotein was required for association of Env with lipid rafts. An Env mutant C787S which eliminated palmitoylation did not abolish Env incorporation into lipid rafts, but prevented virus assembly. Conclusion The results indicate that the long cytoplasmic tail of the SIV Env glycoprotein may govern post-entry replication events and plays a role in the assembly process.

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© 2007 Vzorov et al; licensee BioMed Central Ltd.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 2.0 Generic License (http://creativecommons.org/licenses/by/2.0/).

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