Cholesterol is required in the exit pathway of Semliki Forest virus

Marianne T. Marquardt, Thomas Phalen, Margaret Kielian

Research output: Contribution to journalArticle

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Abstract

The enveloped alphavirus Semliki Forest virus (SFV) infects cells via a membrane fusion reaction triggered by low pH. For fusion to occur cholesterol is required in the target membrane, as demonstrated both in in vitro fusion assays and in vivo for virus infection of a host cell. In this paper we examine the role of cholesterol in postfusion events in the SFV life cycle. Cholesterol-depleted insect cells were transfected with SFV RNA or infected at very high multiplicities to circumvent the fusion block caused by the absence of cholesterol. Under these conditions, the viral spike proteins were synthesized and transported to the site of p62 cleavage with normal kinetics. Surprisingly, the subsequent exit of virus particles was dramatically slowed compared to cholesterol-containing cells. The inhibition of virus production could be reversed by the addition of cholesterol to depleted cells. In contrast to results with SFV, no cholesterol requirement for virus exit was observed for the production of either the unrelated vesicular stomatitis virus or a cholesterol-independent SFV fusion mutant. Thus, cholesterol was only critical in the exit pathway of viruses that also require cholesterol for fusion. These results demonstrate a specific and unexpected lipid requirement in virus exit, and suggest that in addition to its role in fusion, cholesterol is involved in the assembly or budding of SFV.

Original languageEnglish (US)
Pages (from-to)57-65
Number of pages9
JournalJournal of Cell Biology
Volume123
Issue number1
StatePublished - Oct 1993

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Semliki forest virus
Cholesterol
Viruses
Alphavirus
Vesicular Stomatitis
Membrane Fusion
Viral Proteins
Virus Diseases
Life Cycle Stages
Virion
Insects

ASJC Scopus subject areas

  • Cell Biology

Cite this

Cholesterol is required in the exit pathway of Semliki Forest virus. / Marquardt, Marianne T.; Phalen, Thomas; Kielian, Margaret.

In: Journal of Cell Biology, Vol. 123, No. 1, 10.1993, p. 57-65.

Research output: Contribution to journalArticle

Marquardt, Marianne T. ; Phalen, Thomas ; Kielian, Margaret. / Cholesterol is required in the exit pathway of Semliki Forest virus. In: Journal of Cell Biology. 1993 ; Vol. 123, No. 1. pp. 57-65.
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