Search results for "picornavirus"

A Novel Open and Infectious Form of Echovirus 1.

2016

ABSTRACT One of the hallmarks of enterovirus genome delivery is the formation of an uncoating intermediate particle. Based on previous studies of mostly heated picornavirus particles, intermediate particles were shown to have externalized the innermost capsid protein (VP4) and exposed the N terminus of VP1 and to have reduced infectivity. Here, in addition to the native and intact particle type, we have identified another type of infectious echovirus 1 (E1) particle population during infection. Our results show that E1 is slightly altered during entry, which leads to the broadening of the major virion peak in the sucrose gradient. In contrast, CsCl gradient separation revealed that in addit…

Structural Studies Reveal that Endosomal Cations Promote Formation of Infectious Coxsackievirus A9 A-Particles, Facilitating RNA and VP4 Release

2022

Coxsackievirus A9 (CVA9), an enterovirus, is a common cause of pediatric aseptic meningitis and neonatal sepsis. During cell entry, enterovirus capsids undergo conformational changes leading to expansion, formation of large pores, externalization of VP1 N termini, and loss of the lipid factor from VP1. Factors such as receptor binding, heat, and acidic pH can trigger capsid expansion in some enteroviruses. Here, we show that fatty acid-free bovine serum albumin or neutral endosomal ionic conditions can independently prime CVA9 for expansion and genome release. Our results showed that CVA9 treatment with albumin or endosomal ions generated a heterogeneous population of virions, which could b…

Author response: Globally defining the effects of mutations in a picornavirus capsid

2021

Permeability changes of integrin-containing multivesicular structures triggered by picornavirus entry.

2014

Cellular uptake of clustered α2β1-integrin induces the formation of membrane compartments that subsequently mature into a multivesicular body (MVB). Enhanced internalization mediated by clustered integrins was observed upon infection by the picornavirus echovirus 1 (EVI). We elucidated the structural features of virus-induced MVBs (vMVBs) in comparison to antibody-induced control MVBs (mock infection) by means of high-pressure cryo fixation of cells followed by immuno electron tomography during early entry of the virus. Three-dimensional tomograms revealed a marked increase in the size and complexity of these vMVBs and the intraluminal vesicles (ILVs) at 2 and 3.5 hours post infection (p.i.…

Phylogeny and prevalence of kobuviruses in dogs and cats in the UK

2013

AbstractThe kobuviruses represent an emerging genus in the Picornaviridae. Here we have used next generation sequencing and conventional approaches to identify the first canine kobuvirus (CaKoV) from outside the USA. Phylogenetic analysis suggests that a single lineage genotype of CaKoV now exists in Europe and the USA with 94% nucleotide similarity in the coding region. CaKoV was only identified in a single case from a case–control study of canine diarrhoea, suggesting this virus was not a frequent cause of disease in this population. Attempts to grow CaKoV in cell culture failed. Sequence analysis suggested CaKoV was distinct from human Aichi virus (AiV), and unlikely to pose a significan…

Entry of Human Parechovirus 1

2001

ABSTRACT Human parechovirus 1 (HPEV-1) is a prototype member of parechoviruses, a recently established picornavirus genus. Although there is preliminary evidence that HPEV-1 recognizes α V integrins as cellular receptors, our understanding of early events during HPEV-1 infection is still very limited. The aim of this study was to clarify the entry mechanisms of HPEV-1, including the attachment of the virus onto the host cell surface and subsequent internalization. In blocking experiments with monoclonal antibodies against different receptor candidates, antibodies against α V and β 3 integrin subunits, in particular in combination, appeared to be the most efficient ones in preventing the HPE…

Structural and functional analysis of integrin alpha2I domain interaction with echovirus 1.

2004

Integrins are cell surface receptors for several microbial pathogens including echovirus 1 (EV1), a picornavirus. Cryo-electron microscopy revealed that the functional domain (alpha(2)I) of human alpha(2)beta(1) integrin binds to a surface depression on the EV1 capsid. This three-dimensional structure of EV1 bound to alpha(2)I domain provides the first structural details of an integrin interacting with a picornavirus. The model indicates that alpha(2)beta(1) integrin cannot simultaneously bind both EV1 and the physiological ligand collagen. Compared with collagen binding to the alpha(2)I domain, the virus binds with a 10-fold higher affinity but in vitro uncoating of EV1 was not observed as…

Real-time Fluorescence Measurement of Enterovirus Uncoating

2019

Viruses need to open, i.e., uncoat, in order to release their genomes for efficient replication and translation. Especially for non-enveloped viruses, such as enteroviruses, the cues leading to uncoating are less well known. The status of the virus has previously been observed mainly by transmission electron microscopy using negative staining, cryo electron microscopy, X-ray crystallography or gradient separation (reviewed in Tuthill et al., 2010, Myllynen et al., 2016, Ruokolainen et al., 2019). However, monitoring of uncoating has been limited by the lack of methods detecting dynamic changes of the virions. Here, we present a real-time fluorescence based protocol, which detects the viral …

Globally defining the effects of mutations in a picornavirus capsid

2021

The capsids of non-enveloped viruses are highly multimeric and multifunctional protein assemblies that play key roles in viral biology and pathogenesis. Despite their importance, a comprehensive understanding of how mutations affect viral fitness across different structural and functional attributes of the capsid is lacking. To address this limitation, we globally define the effects of mutations across the capsid of a human picornavirus. Using this resource, we identify structural and sequence determinants that accurately predict mutational fitness effects, refine evolutionary analyses, and define the sequence specificity of key capsid-encoded motifs. Furthermore, capitalizing on the derive…

Teschoviruses and sapeloviruses in faecal samples from wild boar in Spain

2013

Teschovirus and Sapelovirus are two genera of the Picornaviridae family, comprising highly variable and heterogeneous enteric viruses, commonly found in faecal samples from domestic pigs. Although both of them are also known to infect wild boar, studies on their presence in these wild suids are scarce. The present study aimed at determining the presence of porcine teschovirus (PTV) and sapelovirus (PSV) in free-living wild boar populations, as well as to study their relationships with similar viruses present in pigs. Fresh faecal samples (n = 63) from wild boar were collected in Doñana Biological Reserve (SW Spain) during 2007 and 2011, and analysed using multiplex RT-PCR for the simultaneo…