HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Free via Open Access: OA OA Free Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Zusinaite, E. Articles by Sarand, I. Search for Related Content PubMed PubMed Citation Articles by Zusinaite, E. Articles by Sarand, I. Agricola Articles by Zusinaite, E. Articles by Sarand, I.

Mutations at the palmitoylation site of non-structural protein nsP1 of Semliki Forest virus attenuate virus replication and cause accumulation of compensatory mutations

Eva usinaite^1,

Kairit Tints^1,2,,

¹ Institute of Molecular and Cell Biology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
² Estonian Biocentre, Riia Street 23, 51010 Tartu, Estonia
³ Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland

Correspondence
Andres Merits
andres.merits{at}ut.ee

The replicase of Semliki Forest virus (SFV) consists of four non-structural proteins, designated nsP1–4, and is bound to cellular membranes via an amphipathic peptide and palmitoylated cysteine residues of nsP1. It was found that mutations preventing nsP1 palmitoylation also attenuated virus replication. The replacement of these cysteines by alanines, or their deletion, abolished virus viability, possibly due to disruption of interactions between nsP1 and nsP4, which is the catalytic subunit of the replicase. However, during a single infection cycle, the ability of the virus to replicate was restored due to accumulation of second-site mutations in nsP1. These mutations led to the restoration of nsP1–nsP4 interaction, but did not restore the palmitoylation of nsP1. The proteins with palmitoylation-site mutations, as well as those harbouring compensatory mutations in addition to palmitoylation-site mutations, were enzymically active and localized, at least in part, on the plasma membrane of transfected cells. Interestingly, deletion of 7 aa including the palmitoylation site of nsP1 had a relatively mild effect on virus viability and no significant impact on nsP1–nsP4 interaction. Similarly, the change of cysteine to alanine at the palmitoylation site of nsP1 of Sindbis virus had only a mild effect on virus replication. Taken together, these findings indicate that nsP1 palmitoylation as such is not the factor determining the ability to bind to cellular membranes and form a functional replicase complex. Instead, these abilities may be linked to the three-dimensional structure of nsP1 and the capability of nsP1 to interact with other components of the viral replicase complex.

These authors contributed equally to this work.

Present address: Protobios OÜ, Akadeemia tee 15, 12618 Tallinn, Estonia.

This article has been cited by other articles:

				K. Kiiver, I. Tagen, E. Zusinaite, N. Tamberg, J. K. Fazakerley, and A. Merits Properties of non-structural protein 1 of Semliki Forest virus and its interference with virus replication J. Gen. Virol., June 1, 2008; 89(6): 1457 - 1466. [Abstract] [Full Text] [PDF]

				K. Tamm, A. Merits, and I. Sarand Mutations in the nuclear localization signal of nsP2 influencing RNA synthesis, protein expression and cytotoxicity of Semliki Forest virus J. Gen. Virol., March 1, 2008; 89(3): 676 - 686. [Abstract] [Full Text] [PDF]