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Putative processing of the astrovirus nonstructural proteins expressed from ORF1a and ORF1b. HEL, putative helicase domain; CC, coiled-coil domain; TM, transmembrane domain; PRO, protease domain; VPg, viral protein genome-linked coding region; HVR, hypervariable region; RdRp, RNA-dependent RNA polymerase motif; P, posttranslational phosphorylation. Triangles depict proteolytic cleavage sites described in the literature (75, 77, 78, 80).
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Human astroviruses (HAtVs) are positive-sense single-stranded RNA viruses that were discovered in 1975. Astroviruses infecting other species, particularly mammalian and avian, were identified and classified into the genera Mamastrovirus and Avastrovirus. Through next-generation sequencing, many new astroviruses infecting different species, includin...
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Context 1
... recruitment of cellular translation initiation factors, analogous to what has been described for caliciviruses (73). The genome is then translated, giving rise to nsP1a1b and nsP1a poly- proteins, which are then cleaved by the viral serine protease (in nsP1a) as well as some cellular proteases, resulting in the individ- ual nonstructural proteins (Fig. 4). The crystal structure of the viral protease has been resolved, showing properties of trypsin- like enzymes with a catalytic Asp-His-Ser triad typical of the serine proteases ...
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... systems with a variety of classic HAstVs re- ported different intermediate and final products (75-79). It appears, however, that proteolytic processing of polyproteins nsP1a1b (around 160 kDa) produces the nsP1b protein (RdRp) (around 57 kDa) and the nsP1a protein (around 102 kDa), which is subsequently cleaved to yield several mature products (Fig. 4). Several putative transmembrane domains that could help in driv- ing and anchoring the nonstructural replication complexes on cellular membranes have been identified in the nsP1a polypro- teins (13,62). Four potential cleavage sites have been proposed in the nsP1a protein, specifically between residues Ala 174 and His 175 , between Val ...
Citations
... Notably, a high viral copy number was found in the gut of the GAstV-1 infected group, suggesting that the gut is also an important organ for viral invasion and replication. However, no significant lesions were found in the gut in this study, possibly because the histological changes and inflammatory response of the host's gut to astrovirus infection were relatively low [27]. In addition, the kidney and intestine can be used as options for GAstV-1 detection due to the high viral copy numbers in these tissues. ...
Goose astrovirus genotype 1 (GAstV-1) has emerged in goose farms in some provinces of China in recent years and is considered to be one of the pathogens of gout in goslings in China. However, few studies have been conducted on the dynamic distribution, tissue tropism, and pathogenesis of GAstV-1 in goslings. In 2022, an epidemiological investigation of goose astrovirus (GAstV) in goslings was conducted in seven provinces of China. During the investigation, a GAstV-1 designated as GAstV-JSXZ was identified in the kidney of an 8-day-old gosling and was successfully isolated from a goose embryo. The full genome sequence of GAstV-JSXZ was determined using the next-generation sequencing technique. The complete genome of GAstV-JSXZ was 7299-nt-long. Interestingly, the phylogenetic analysis revealed that Chinese GAstV-1 has formed two distinct subgroups based on the ORF 2 genomes, designated GAstV-1 1a and GAstV-1 1b. The GAstV-JSXZ shared the highest identity with GAstV-1 1a strain FLX and TZ03 in nucleotides (ORF1a: 98.3–98.4%; ORF1b: 92.3–99.1%; ORF2: 95.8–98.8%) and amino acid sequences (ORF1a: 99.4–99.5%; ORF1b: 98.2–98.8%; ORF2: 97.0–99.4%). To evaluate the pathogenicity of GAstV-1, 1-day-old goslings were inoculated with the virus by oral and subcutaneous injection routes, respectively. The results revealed that the virus causes extensive pathological organ damage, especially in the kidney, liver, and thymus. Virus-specific genomic RNA could be detected in the cloacal swabs and tissues of infected goslings throughout the experiment. The viral copy numbers examined in the kidney and intestine were the highest, followed by the liver and spleen. These results are likely to provide a new understanding of the pathogenicity of GAstV-1 in geese.
... Introduction Astroviruses, first described in 1975 and belonging to the Astroviridae family, are non-enveloped, positive-sense single-stranded RNA viruses known to infect a wide range of avian and mammalian species [1]. Classical human astroviruses (HAstVs) include serotypes 1-8, and are associated with acute or severe gastroenteritis mainly in children; almost 90% of children possess detectable antibodies to one of the classical HAstV serotypes [2][3][4][5]. ...
Human astrovirus (HAstV) is a known cause of viral gastroenteritis in children worldwide, but HAstV can cause also severe and systemic infections in immunocompromised patients. There are three clades of HAstV: classical, MLB, and VA/HMO. While all three clades are found in gastrointestinal samples, HAstV-VA/HMO is the main clade associated with meningitis and encephalitis in immunocompromised patients. To understand how the HAstV-VA/HMO can infect the central nervous system, we investigated its sequence-divergent capsid spike, which functions in cell attachment and may influence viral tropism. Here we report the high-resolution crystal structures of the HAstV-VA1 capsid spike from strains isolated from patients with gastrointestinal and neuronal disease. The HAstV-VA1 spike forms a dimer and shares a core beta-barrel structure with other astrovirus capsid spikes but is otherwise strikingly different, suggesting that HAstV-VA1 may utilize a different cell receptor, and an infection competition assay supports this hypothesis. Furthermore, by mapping the capsid protease cleavage site onto the structure, the maturation and assembly of the HAstV-VA1 capsid is revealed. Finally, comparison of gastrointestinal and neuronal HAstV-VA1 sequences, structures, and antigenicity suggests that neuronal HAstV-VA1 strains may have acquired immune escape mutations. Overall, our studies on the HAstV-VA1 capsid spike lay a foundation to further investigate the biology of HAstV-VA/HMO and to develop vaccines and therapeutics targeting it.
... for visualizing recombination in viral sequences. A common (and generally known) feature of these virus families was frequent recombination between genome regions encoding nonstructural and structural proteins [67,[70][71][72]. However, the recombination profiles within these genome regions were contrasting. ...
The 2023 International Virus Bioinformatics Meeting was held in Valencia, Spain, from 24–26 May 2023, attracting approximately 180 participants worldwide. The primary objective of the conference was to establish a dynamic scientific environment conducive to discussion, collaboration, and the generation of novel research ideas. As the first in-person event following the SARS-CoV-2 pandemic, the meeting facilitated highly interactive exchanges among attendees. It served as a pivotal gathering for gaining insights into the current status of virus bioinformatics research and engaging with leading researchers and emerging scientists. The event comprised eight invited talks, 19 contributed talks, and 74 poster presentations across eleven sessions spanning three days. Topics covered included machine learning, bacteriophages, virus discovery, virus classification, virus visualization, viral infection, viromics, molecular epidemiology, phylodynamic analysis, RNA viruses, viral sequence analysis, viral surveillance, and metagenomics. This report provides rewritten abstracts of the presentations, a summary of the key research findings, and highlights shared during the meeting.
... Mamastrovirus comprises AstVs detected in mammals, and Avastrovirus includes those identified in birds. AstVs were initially thought to be highly species-specific [15], but evidence of some AstVs detected in various host species indicates the ability of these viruses to cross the species barrier. Moreover, the recent identification of two novel groups of human AstVs-namely Melbourne (AstV-MLB) and Virginia/human-mink-ovine (AstV-VA/HMO), highly divergent from classic human AstVs, and genetically closer to animal AstVs-has suggested their putative zoonotic origin [16][17][18]. ...
... Further investigations are thus needed to better characterize this monophyletic group. However, the classification of AstVs being based on the capsid gene [15], a phylogeny based on the complete capsid gene is needed to confirm this hypothesis. ...
Astroviruses (AstVs), enteroviruses (EVs), and caliciviruses (CaVs) infect several vertebrate taxa. Transmitted through the fecal–oral route, these enteric viruses are highly resistant and can survive in the environment, thereby increasing their zoonotic potential. Here, we screened for AstVs, EVs, and CaVs to investigate the role of domestic animals in the emergence of zoonoses, because they are situated at the human/wildlife interface, particularly in rural forested areas in Central Africa. Rectal swabs were obtained from 123 goats, 41 sheep, and 76 dogs in 10 villages located in northeastern Gabon. Extracted RNA reverse-transcribed into cDNA was used to detect AstVs, EVs, and CaVs by amplification of the RNA-dependent RNA polymerase (RdRp), or capsid protein (VP1) gene using PCR. A total of 23 samples tested positive, including 17 goats for AstVs, 2 goats, 2 sheep, 1 dog for EVs, and 1 dog for CaVs. Phylogenetic analyses revealed that AstV RdRp sequences clustered with sheep-, goat-, or bovine-related AstVs. In addition, one goat and two sheep VP1 sequences clustered with caprine/ovine-related Evs within the Enterovirus G species, and the CaV was a canine vesivirus. However, human-pathogenic Evs, EV-B80 and EV-C99, were detected in goats and dogs, raising questions on the maintenance of viruses able to infect humans.
... The fact that astroviruses are pathogenic to humans was widely acknowledged by researchers in Thailand in 1991 [61]. Abundant evidence proved that astroviruses were a major cause of severe acute gastroenteritis in children, elderly people, and immunocompromised individuals (persons with a weakened immune system) [62][63][64]. ...
In this study, we analyzed the transcriptomes of RNA and DNA viruses from the oligotrophic water of Lake Baikal and the effluent from wastewater treatment plants (WWTPs) discharged into the lake from the towns of Severobaikalsk and Slyudyanka located on the lake shores. Given the uniqueness and importance of Lake Baikal, the issues of biodiversity conservation and the monitoring of potential virological hazards to hydrobionts and humans are important. Wastewater treatment plants discharge treated effluent directly into the lake. In this context, the identification and monitoring of allochthonous microorganisms entering the lake play an important role. Using high-throughput sequencing methods, we found that dsDNA-containing viruses of the class Caudoviricetes were the most abundant in all samples, while Leviviricetes (ssRNA(+) viruses) dominated the treated water samples. RNA viruses of the families Nodaviridae, Tombusviridae, Dicitroviridae, Picobirnaviridae, Botourmiaviridae, Marnaviridae, Solemoviridae, and Endornavirida were found in the pelagic zone of three lake basins. Complete or nearly complete genomes of RNA viruses belonging to such families as Dicistroviridae, Marnaviridae, Blumeviridae, Virgaviridae, Solspiviridae, Nodaviridae, and Fiersviridae and the unassigned genus Chimpavirus, as well as unclassified picorna-like viruses, were identified. In general, the data of sanitary/microbiological and genetic analyses showed that WWTPs inadequately purify the discharged water, but, at the same time, we did not observe viruses pathogenic to humans in the pelagic zone of the lake.
... Astroviruses are distributed worldwide and infect a broad spectrum of host species, including mammals, birds, fish, and reptiles [1,2]. In humans, astroviral infection is associated with gastrointestinal disease but may also affect the nervous system, causing fatal encephalitis [3][4][5][6][7][8][9]. ...
... In humans, astroviral infection is associated with gastrointestinal disease but may also affect the nervous system, causing fatal encephalitis [3][4][5][6][7][8][9]. The classical human astroviruses (HAstVs) are major causes of gastroenteritis in children [2,10]. These classical strains are genetically related and belong to the same virus species, Mamastrovirus 1, which has eight serotypes (HAstV-1-8) [11]. ...
Astroviruses are small nonenveloped single-stranded RNA viruses with a positive sense genome. They are known to cause gastrointestinal disease in a broad spectrum of species. Although astroviruses are distributed worldwide, a gap in knowledge of their biology and disease pathogenesis persists. Many positive-sense single-stranded RNA viruses show conserved and functionally important structures in their 5′ and 3′ untranslated regions (UTRs). However, not much is known about the role of the 5′ and 3′ UTRs in the viral replication of HAstV-1. We analyzed the UTRs of HAstV-1 for secondary RNA structures and mutated them, resulting in partial or total UTR deletion. We used a reverse genetic system to study the production of infectious viral particles and to quantify protein expression in the 5′ and 3′ UTR mutants, and we established an HAstV-1 replicon system containing two reporter cassettes in open reading frames 1a and 2, respectively. Our data show that 3′ UTR deletions almost completely abolished viral protein expression and that 5′ UTR deletions led to a reduction in infectious virus particles in infection experiments. This indicates that the presence of the UTRs is essential for the life cycle of HAstV-1 and opens avenues for further research.
... Astrovirus are single-stranded positive sense RNA (+ssRNA) viruses. They are non-enveloped with 50 an icosahedral morphology and a genome length of approximately 6.2 to 7.7 Kb [1] . They infect a 51 wide variety of both domestic and wild marine and terrestrial mammals, including humans 52 (Mamastrovirus) as well as avian hosts (Avastrovirus) [2] . ...
Astroviruses (AstVs) have been discovered in over 80 animal species including diverse bat species and avian species. A study on Astrovirus circulation and diversity in different insectivorous and frugivorous chiropteran species roosting in trees, caves and building basements was carried out at 11 different sites across Zimbabwe. Pooled and individual faecal sampling methods were used for this study, collection date ranged from June 2016 to July 2021. In two sites, Magweto and Chirundu, sampling was carried out at monthly intervals from August 2020 to July 2021. Astroviruses and bat mitochondrial genes were amplified using pan-AstVs and CytB /12S RNA PCR systems respectively. Phylogenetic analysis of the RdRp Astrovirus sequences revealed a high genetic diversity of astroviruses. All the bat astroviruses tested in this study clustered with the Mamastrovirus genus. Two distinct groups of the amplified sequences were identified. One group comprised of sequences isolated from Hipposideros, Rhinolophus and E. helvum spp clustered with Human Astrovirus strains: HuAstV types1-6, HuAstV-MLB1-3 and HuAstV-VA-1. A second group comprised of the majority of the sequences clustered with different strains of Bat AstVs. Results from the longitudinal study at Magweto and Chirundu showed an overall AstV prevalence of 13.7% and 10.4% respectively. Peaks of AstV infection at Chirundu coincided with the period when juveniles are 4-6 months old. Coinfection of bats with CoVs and AstVs at Magweto and Chirundu sites was 2.6% and 3.5% respectively.
... In wildlife, they have been mainly described in a large diversity of bat species from Asia, Europe, and Africa (Chu et al. 2008;Zhu et al. 2009;Dufkova et al. 2015;Fischer et al. 2016;Rougeron et al. 2016;Hoarau et al. 2018). Recent phylogenetic studies suggest that AstVs are characterized by frequent cross-species transmission (Mendenhall, Smith, et Vijaykrishna 2015), and AstVs with potential zoonotic transmission have been reported worldwide, highlighting the need for improved knowledge on their biology (Bosch, Pintó, et Guix 2014). ...
... In wildlife, they have been mainly described in a large diversity of bat species from Asia, Europe, and Africa (Chu et al. 2008;Zhu et al. 2009;Dufkova et al. 2015;Fischer et al. 2016;Rougeron et al. 2016;Hoarau et al. 2018). Recent phylogenetic studies suggest that AstVs are characterized by frequent cross-species transmission (Mendenhall, Smith, et Vijaykrishna 2015), and AstVs with potential zoonotic transmission have been reported worldwide, highlighting the need for improved knowledge on their biology (Bosch, Pintó, et Guix 2014). ...
... In wildlife, they have been mainly described in a large diversity of bat species from Asia, Europe, and Africa (Chu et al. 2008;Zhu et al. 2009;Dufkova et al. 2015;Fischer et al. 2016;Rougeron et al. 2016;Hoarau et al. 2018). Recent phylogenetic studies suggest that AstVs are characterized by frequent cross-species transmission (Mendenhall, Smith, et Vijaykrishna 2015), and AstVs with potential zoonotic transmission have been reported worldwide, highlighting the need for improved knowledge on their biology (Bosch, Pintó, et Guix 2014). ...
