Competitive fitness in coronaviruses is not correlated with size or number of double-membrane vesicles under reduced-temperature growth conditions.


Autoria(s): Al-Mulla, Hawaa M N; Turrell, Lauren; Smith, Nicola M; Payne, Luke; Baliji, Surendranath; Züst, Roland; Thiel, Volker Earl; Baker, Susan C; Siddell, Stuart G; Neuman, Benjamin W
Data(s)

01/04/2014

Resumo

Positive-stranded viruses synthesize their RNA in membrane-bound organelles, but it is not clear how this benefits the virus or the host. For coronaviruses, these organelles take the form of double-membrane vesicles (DMVs) interconnected by a convoluted membrane network. We used electron microscopy to identify murine coronaviruses with mutations in nsp3 and nsp14 that replicated normally while producing only half the normal amount of DMVs under low-temperature growth conditions. Viruses with mutations in nsp5 and nsp16 produced small DMVs but also replicated normally. Quantitative reverse transcriptase PCR (RT-PCR) confirmed that the most strongly affected of these, the nsp3 mutant, produced more viral RNA than wild-type virus. Competitive growth assays were carried out in both continuous and primary cells to better understand the contribution of DMVs to viral fitness. Surprisingly, several viruses that produced fewer or smaller DMVs showed a higher fitness than wild-type virus at the reduced temperature, suggesting that larger and more numerous DMVs do not necessarily confer a competitive advantage in primary or continuous cell culture. For the first time, this directly demonstrates that replication and organelle formation may be, at least in part, studied separately during infection with positive-stranded RNA virus. IMPORTANCE The viruses that cause severe acute respiratory syndrome (SARS), poliomyelitis, and hepatitis C all replicate in double-membrane vesicles (DMVs). The big question about DMVs is why they exist in the first place. In this study, we looked at thousands of infected cells and identified two coronavirus mutants that made half as many organelles as normal and two others that made typical numbers but smaller organelles. Despite differences in DMV size and number, all four mutants replicated as efficiently as wild-type virus. To better understand the relative importance of replicative organelles, we carried out competitive fitness experiments. None of these viruses was found to be significantly less fit than wild-type, and two were actually fitter in tests in two kinds of cells. This suggests that viruses have evolved to have tremendous plasticity in the ability to form membrane-associated replication complexes and that large and numerous DMVs are not exclusively associated with efficient coronavirus replication.

Formato

application/pdf

Identificador

http://boris.unibe.ch/66649/1/mBio-2014-Al-Mulla-.pdf

Al-Mulla, Hawaa M N; Turrell, Lauren; Smith, Nicola M; Payne, Luke; Baliji, Surendranath; Züst, Roland; Thiel, Volker Earl; Baker, Susan C; Siddell, Stuart G; Neuman, Benjamin W (2014). Competitive fitness in coronaviruses is not correlated with size or number of double-membrane vesicles under reduced-temperature growth conditions. mBio, 5(2), e01107-e01113. American Society for Microbiology 10.1128/mBio.01107-13 <http://dx.doi.org/10.1128/mBio.01107-13>

doi:10.7892/boris.66649

info:doi:10.1128/mBio.01107-13

info:pmid:24692638

urn:issn:2150-7511

Idioma(s)

eng

Publicador

American Society for Microbiology

Relação

http://boris.unibe.ch/66649/

Direitos

info:eu-repo/semantics/openAccess

Fonte

Al-Mulla, Hawaa M N; Turrell, Lauren; Smith, Nicola M; Payne, Luke; Baliji, Surendranath; Züst, Roland; Thiel, Volker Earl; Baker, Susan C; Siddell, Stuart G; Neuman, Benjamin W (2014). Competitive fitness in coronaviruses is not correlated with size or number of double-membrane vesicles under reduced-temperature growth conditions. mBio, 5(2), e01107-e01113. American Society for Microbiology 10.1128/mBio.01107-13 <http://dx.doi.org/10.1128/mBio.01107-13>

Palavras-Chave #630 Agriculture
Tipo

info:eu-repo/semantics/article

info:eu-repo/semantics/publishedVersion

PeerReviewed