Coupling of replication and assembly in flaviviruses

Apte-Sengupta, Swapna; Sirohi, Devika; Kühn, Richard

doi:10.1016/j.coviro.2014.09.020

Cited by 166 publications

(172 citation statements)

References 84 publications

Supporting

Mentioning

166

Contrasting

Unclassified

Order By: Relevance

“…Remarkably, our results confi rmed that WNV multiplication, including RNA replication and infectious virus production, was increased in NPA fi broblasts, which again support that the related fl aviviruses ( 12 ). Flavivirus replication complexes, including those of WNV, are developed in highly modifi ed membranes derived from the ER ( 3-6 ), and both RNA replication and particle biogenesis are coupled in these membranous structures ( 4 ). Along this line, because both the fl aviviral envelope and the replication complex are enriched in SM ( 8,12 ), we propose that SM could positively contribute to both RNA replication and particle biogenesis during WNV infection.…”

Section: Discussionsupporting

confidence: 78%

Host sphingomyelin increases West Nile virus infection in vivo

Martín-Acebes

Gabandé‐Rodríguez

García-Cabrero

et al. 2016

Journal of Lipid Research

View full text Add to dashboard Cite

The fl avivirus, West Nile virus (WNV), is a neurotropic enveloped plus-strand RNA virus transmitted through the bite of mosquitoes. This virus is responsible for recurrent outbreaks of febrile illness and meningoencephalitis worldwide, accounting for hundreds of human deaths every year ( 2 ). The WNV lifecycle is intimately associated to cellular lipids, and RNA replication and virion biogenesis are coupled into highly remodeled intracellular membranes ( 3, 4 ). In a parallel manner to that described for other fl aviviruses, both RNA replication and acquisition of lipid envelope are associated to specialized membranous structures derived from the endoplasmic reticulum (ER) ( 3-6 ). To generate this adequate environment for viral multiplication, WNV promotes the synthesis and accumulation of specifi c lipids (fatty acids, cholesterol, glycerophospholipids, and sphingolipids) within infected cells ( 5,(7)(8)(9). This selective manipulation of host cell lipid metabolism is not a unique feature of WNV infection, as it is also observed in cells infected with other fl aviviruses ( 10-12 ).Among the cellular lipids co-opted by WNV, sphingolipids merit special attention because they are particularly enriched in the nervous system, a major target tissue during WNV infection ( 13,14 ). Sphingolipids derive from sphingosine, a long-chain amino alcohol that is acylated with a long-chain fatty acid to give ceramide, which

show abstract

Section: Discussionsupporting

confidence: 78%

Host sphingomyelin increases West Nile virus infection in vivo

Martín-Acebes

Gabandé‐Rodríguez

García-Cabrero

et al. 2016

Journal of Lipid Research

View full text Add to dashboard Cite

show abstract

“…Blockage of infectious virus production has been described for other viruses treated with drugs affecting lipid metabolism (31,40). In this regard, it should be considered that replication and assembly of viral particles are coupled processes in flaviviruses (5). This may explain our results showing that the alteration of lipid metabolism could affect both processes.…”

Section: Discussionsupporting

confidence: 62%

“…The replication of the viral genomic RNA and flavivirus nascent virion assembly take place in modified membranes from the endoplasmic reticulum (4)(5)(6)(7). To build an adequate microenvironment to support viral replication and particle biogenesis, flaviviruses rearrange host cell lipid metabolism by promoting the synthesis and accumulation of specific cellular lipids (i.e., fatty acids, glycerophospholipids [GPLs], sphingolipids [SLs], and cholesterol) (8)(9)(10)(11)(12)(13)(14)(15).…”

mentioning

confidence: 99%

Modification of the Host Cell Lipid Metabolism Induced by Hypolipidemic Drugs Targeting the Acetyl Coenzyme A Carboxylase Impairs West Nile Virus Replication

Merino-Ramos

Vázquez-Calvo

Casas

et al. 2016

Antimicrob Agents Chemother

View full text Add to dashboard Cite

West Nile virus (WNV) is a mosquito-borne neurotropic flavivirus responsible for recurrent outbreaks of meningitis and encephalitis affecting humans, horses, and birds in Africa, Europe, Asia, Oceania, and America (1). A great effort has been devoted in the past several years to decipher the molecular biology of WNV and its interaction with the host immune system (2, 3). Nevertheless, no licensed vaccine or therapy for human use against this pathogen is yet available.The flavivirus life cycle (including that of WNV) is intimately associated with host cell lipids. The replication of the viral genomic RNA and flavivirus nascent virion assembly take place in modified membranes from the endoplasmic reticulum (4-7). To build an adequate microenvironment to support viral replication and particle biogenesis, flaviviruses rearrange host cell lipid metabolism by promoting the synthesis and accumulation of specific cellular lipids (i.e., fatty acids, glycerophospholipids [GPLs], sphingolipids [SLs], and cholesterol) (8-15). This makes the pharmacological manipulation of cellular lipids an attractive antiviral strategy against WNV and related flaviviruses (13,14,16,17).The first steps of lipid biogenesis involve the synthesis and elongation of fatty acids, which provide the building blocks for the synthesis of more-complex lipids. Hence, fatty acid synthesis and elongation have become key targets for antiviral therapy (13,18,19). Regarding the flaviviruses, the pharmacological blockage of the fatty acid synthase FASN (which catalyzes the synthesis of palmitate from acetyl coenzyme A [acetyl-CoA] and malonylCoA into long-chain saturated fatty acids) reduced the viral replication (11, 13). The enzyme preceding FASN in the fatty acid biosynthetic route is the acetyl-CoA carboxylase (ACC), which catalyzes the carboxylation of acetyl-CoA to malonyl-CoA. Due to its rate-limiting role in fatty acid synthesis, ACC is currently a target of increasing interest within the pharmacological industry (20, 21). However, to our knowledge, the involvement of ACC in the replication of WNV, or other related flaviviruses, has not yet been evaluated.In this work, we have shown that ACC inhibitors alter the cellular lipid composition and reduce the levels of WNV infection in cultured cells. Furthermore, infection by Usutu virus (USUV; a related emerging flavivirus [22]) was also inhibited by the drugs used. Our results point to ACC as a potential druggable antiviral target against WNV and related flaviviruses. MATERIALS AND METHODSCells, viruses, infections, and virus titrations. All infectious virus manipulations were performed in biosafety level 3 (BSL-3) facilities. Vero, HeLa, and Neuro2a (N2a) cell lines were cultured as described previously (10, 23). Cells were incubated with the corresponding virus, WNV strain NY99 or USUV strain SAAR-1776 (24), for 1 h at 37°C; viral inoculum was removed; and infected cells were incubated in culture medium containing 1% fetal bovine serum (time that was considered 1 h postinfection [p.i.]).

show abstract

“…Immature viruses carry 60 spikes of trimers of prM-E heterodimers (3,4) and assemble by budding into the lumen of the endoplasmic reticulum (ER) (5). This process is driven by lateral interactions between prM-E oligomers and as yet undefined interactions with the capsid (6). How the nucleocapsid is formed and integrated into flavivirus particles is still unresolved.…”

Section: Importancementioning

confidence: 99%

Membrane Anchors of the Structural Flavivirus Proteins and Their Role in Virus Assembly

Blazevic

Rouha

Bradt

et al. 2016

J Virol

View full text Add to dashboard Cite

The structural proteins of flaviviruses carry a unique set of transmembrane domains (TMDs) at their C termini that are derived from the mode of viral polyprotein processing. They function as internal signal and stop-transfer sequences during protein translation, but possible additional roles in protein interactions required during assembly and maturation of viral particles are ill defined. To shed light on the role of TMDs in these processes, we engineered a set of tick-borne encephalitis virus mutants in which these structural elements were replaced in different combinations by the homologous sequences of a distantly related flavivirus (Japanese encephalitis virus). The effects of these modifications were analyzed with respect to protein synthesis, viral particle secretion, specific infectivity, and acidic-pH-induced maturation processes. We provide evidence that interactions involving the double-membrane anchor of the envelope protein E (a unique feature compared to other viral fusion proteins) contribute substantially to particle assembly, stability, and maturation. Disturbances of the inter-and intra-TMD interactions of E resulted in the secretion of a larger proportion of capsidless subviral particles at the expense of whole virions, suggesting a possible role in the still incompletely understood mechanism of capsid integration during virus budding. In contrast, the TMD initially anchoring the C protein to the endoplasmic reticulum membrane does not appear to take part in envelope protein interactions. We also show that E TMDs are involved in the envelope protein rearrangements that are triggered by acidic pH in the trans-Golgi network and represent a hallmark of virus maturation. IMPORTANCEThe assembly of flaviviruses occurs in the endoplasmic reticulum and leads to the formation of immature, noninfectious particles composed of an RNA-containing capsid surrounded by a lipid membrane, with the two integrated envelope proteins, prM and E, arranged in an icosahedral lattice. The mechanism by which the capsid is formed and integrated into the budding viral envelope is currently unknown. We provide evidence that the transmembrane domains (TMDs) of E are essential for the formation of capsid-containing particles and that disturbances of these interactions lead to the preferential formation of capsidless subviral particles at the expense of whole virions. E TMD interactions also appear to be essential for the envelope protein rearrangements required for virus maturation and for the generation of infectious virions. Our data thus provide new insights into the biological functions of E TMDs and extend their role during viral polyprotein processing to additional functions in particle assembly and maturation.T he genus Flavivirus in the family Flaviviridae comprises 53 taxonomically recognized species (1), including the humanpathogenic mosquito-borne dengue, Zika, yellow fever, Japanese encephalitis, and West Nile viruses as well as tick-borne encephalitis virus (TBEV) (2). Flaviviruses are small enveloped po...

show abstract

Coupling of replication and assembly in flaviviruses

Cited by 166 publications

References 84 publications

Host sphingomyelin increases West Nile virus infection in vivo

Host sphingomyelin increases West Nile virus infection in vivo

Modification of the Host Cell Lipid Metabolism Induced by Hypolipidemic Drugs Targeting the Acetyl Coenzyme A Carboxylase Impairs West Nile Virus Replication

Membrane Anchors of the Structural Flavivirus Proteins and Their Role in Virus Assembly

Contact Info

Product

Resources

About