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Grove, J.

Publications and source records attributed to Grove, J..

At least 19 recordsLinked to original sources

Systematic exploration of predicted quaternary structures within pandemic-relevant viral proteomes

Mechanistic understanding of viral protein-protein interactions enables global health security and pandemic preparedness, yet experimental characterisation remains difficult, costly, and often restricted to specialised laboratories. Here, we describe an in silico campaign using AlphaFold2 and AlphaFold-Multimer to predict monomers and dimer structures within 2,812 viral proteomes from 23 viral families relevant to human health. We report high-confidence predicted structures of 5,279 hetero-, and 2,749 homo-dimers. Structural clustering of interfaces reduces the set fivefold to 1,598 consolidated by form and function, of which 471 (29.5%) lacked detectable similarity to experimentally determined interfaces in the PDB. These clusters yielded two notable findings: new data on vaccinology-relevant glycoproteins, and accurate prediction of the specificity and cleavage-site recognition of viral proteases, which are targets for anti-viral development. Viral monomers and high-confidence dimers are available for interactive browsing in the Pandemic Preparedness Portal of the AlphaFold Database (https://alphafold.ebi.ac.uk/), and the full dataset is available for bulk download.

bioinformatics↗

SARS-CoV-2 Spike H655Y drives protease preference but does not dictate cellular tropism

Throughout the COVID-19 pandemic, SARS-CoV-2 has undergone rapid adaptation, with the Omicron variant exhibiting an unexpected shift towards upper airway infection and preference for membrane fusion activated by endosomal cathepsins, a reversion to ancestral sarbecovirus entry mechanisms. This phenotype coincides with convergent acquisition of the spike mutation H655Y, which reduces TMPRSS2-mediated activation. Here, using a comprehensive panel of 13 spikes of SARS-CoV-2 variants, we interrogated whether H655Y-mediated protease switching explains Omicrons upper airway phenotype, challenging several existing hypotheses, from spike stability, shedding and acquired intra-molecular interactions by H655Y. Our findings reveal that protease preference and tissue tropism are mechanistically uncoupled. While spike pre-processing by furin determines protease preference in pre-Omicron variants, this relationship breaks down in H655Y-bearing viruses. Notably, mutations in the NTD and RBD of BA.2.86 can override the H655Y phenotype entirely, indicating that RBD-mediated interactions, rather than protease usage, represent the critical determinants of Omicrons upper airway adaptation. This work reframes our understanding of coronavirus spike evolution, revealing that tissue tropism operates through mechanisms fundamentally distinct from those dictating protease preference.

microbiology↗

Inhibition of VP2-mediated entry: a potential antiviral strategy to treat or prevent calicivirus disease

The Caliciviridae include many notable human and animal pathogens, including norovirus and sapovirus, which cause outbreaks of acute gastroenteritis. We previously demonstrated that, following receptor engagement, feline calicivirus (FCV) assembles a portal structure at a unique capsid three-fold axis. This comprises twelve copies of the minor capsid protein VP2 and is essential for genome delivery. We designed a short peptide based on our structure data that occludes the VP2 binding sites on the capsid surface, to prevent assembly of the VP2 portal and thereby halt the viral entry mechanism. Incubation with low micromolar concentrations of the peptide considerably reduced the infectivity of two laboratory strains and four clinical isolates of FCV associated with respiratory or virulent-systemic disease. Cryo-electron microscopy structures of FCV virions complexed with the peptide confirmed that the peptide occupies the VP2 binding site on the major capsid protein VP1, preventing portal assembly and subsequent genome delivery. Our data show that targeting VP2 is a viable antiviral approach to preventing calicivirus infection, with potential for the treatment or prevention of norovirus disease.

microbiology↗

Cryo-EM of a Divergent Herpesvirus Reveals Structural Conservation and Novelty Including a Portal-Vertex Tegument Protein with Multiple Macrodomain-like Folds

Ictalurid herpesvirus 1 (channel catfish virus) is an evolutionarily distant relative of human herpesviruses, from which it is thought to have diverged >400M years ago. Using cryogenic electron microscopy (cryo-EM) combined with symmetry-breaking and particle subtraction approaches, we determined structures of both the immature capsid and virion of IcHV-1. Due to limited genome annotation, we used the machine learning-based tool ModelAngelo for de novo model building, enabling unambiguous protein identification even at marginal resolutions. Notably, the IcHV-1 virion was found to have a substantial and elaborate portal-vertex associated tegument (PVAT) complex. Overall, we determined the identities and structures of ten IcHV-1 proteins: the major capsid protein; the triplex proteins; two novel virion-associated inner tegument proteins; the portal protein; and a further four PVAT proteins. Our findings reveal a high degree of fold conservation in the core capsid proteins when compared with those of human herpesviruses, but also considerable structural novelty, including for the first time in a herpesvirus, identification of a protein that has four putative macrodomains.

microbiology↗

Yellow fever vaccine propagation in primary human hepatocytes triggers antiviral and cytolytic responses

Yellow fever virus (YFV) infection can cause severe-to-fatal liver damage in humans, while immunization with the attenuated 17D vaccine strain has an excellent safety record, priming protective host immunity in the absence of pathology. To investigate virus-host correlates associated with these differential clinical outcomes, we combined YFV genome-level evolutionary analyses with investigations of vaccine and virulent strain hepatotropism. Evolutionary analyses confirmed purifying selection is the dominant force driving global YFV genome divergence, with functional constraints associated with the YFV transmission cycle selecting against vaccine attenuating mutations in virulent strains. In immune deficient hepatoma cells, 17D exhibited enhanced early propagation, spreading and apoptosis induction when compared to virulent strains. Ex vivo infections performed in primary human hepatocytes (PHH) from multiple donors confirmed robust propagation of both 17D and virulent YFV strains. RNA-sequencing revealed consistent and shared induction of IFNB and IFNL1-4, modulating overlapping gene programs associated with antiviral responses, immunity, chemotaxis and inflammation, cell-death, metabolic reprogramming and protein translation. Subtle differences in virion production kinetics and the magnitude and tempo of PHH transcriptional responses were observed. Antiviral responses to 17D were activated earlier while responses to virulent YFV were delayed but enhanced, mirroring virus propagation kinetics. More broadly, cellular responses to YFV infection are likely dominated by paracrine IFN signalling, with enriched LRP1 expression coupled with impaired IFN production in PHH contributing to YFVs robust hepatotropism. In summary, we demonstrate comparable propagation kinetics and PHH transcriptional responses to vaccine and virulent YFV strains, highlighting impaired hepatotropism is not a correlate of vaccine attenuation. These data imply that unknown barriers restrict liver access and associated organ pathology upon vaccination with 17D.

microbiology↗

Integrated analysis of protein sequence and structureredefines viral diversity and the taxonomy of the Flaviviridae

The Flaviviridae are a family of non-segmented positive-sense enveloped RNA viruses containing significant pathogens including hepatitis C virus and yellow fever virus. Recent large-scale metagenomic surveys have identified many diverse RNA viruses related to classical orthoflaviviruses and pestiviruses but quite different genome lengths and configurations, and with a hugely expanded host range that spans multiple animal phyla, including molluscs, cnidarians and stramenopiles,, and plants. Grouping of RNA-directed RNA polymerase (RdRP) hallmark gene sequences of flavivirus and flavi-like viruses into four divergent clades and multiple lineages within them was congruent with helicase gene phylogeny, PPHMM profile comparisons, and comparison of RdRP protein structure predicted by AlphFold2. These results support their classification into the established order, Amarillovirales, in three families (Flaviviridae, Pestiviridae, and Hepaciviridae), and 14 genera. This taxonomic framework informed by RdRP hallmark gene evolutionary relationships provides a stable reference from which major genome re-organisational events can be understood.

microbiology↗

Viro3D: a comprehensive database of virus protein structure predictions

Viruses are intracellular parasites of organisms from all domains of life. They infect and cause disease in humans, animals and plants but also play crucial roles in the ecology of microbial communities. Tolerance to genetic change, high-mutation rates, adaptations to hosts and immune escape has driven high divergence of viral genes, hampering their functional annotation and phylogenetic inference. The protein structure is more conserved than sequence and can be used for searches of distant homologs and evolutionary analysis of divergent proteins. Structures of viral proteins are traditionally underrepresented in public databases, but recent advances in protein structure prediction allows us to address this issue. Combining two state-of-the-art approaches, AlphaFold2-ColabFold and ESMFold, we predicted models for 85,000 proteins from 4,400 human and animal viruses, expanding the structural coverage for viral proteins by 30 times compared to experimental structures. We also performed structural and network analyses of the models to demonstrate their utility for functional annotation and inference of distant phylogenetic relationships. Taking this approach, we examined the deep evolutionary history of viral class-I fusion glycoproteins, gaining insights on the origins of coronavirus spike protein. To enable further discoveries, we have created Viro3D (https://viro3d.cvr.gla.ac.uk/), a virus species-centred protein structure database. It allows users to search, browse and download protein models from a virus of interest and explore similar structures present in other virus species. This resource will facilitate fundamental molecular virology, investigation of virus evolution, and may enable structure-informed design of therapies and vaccines.

microbiology↗

Tunicate metatranscriptomes reveal ancient virus-host co-divergence and inter-order recombination in the evolutionary history of disease-causing viruses

Tunicates are a key transitional taxon in animal evolution as the closest extant invertebrate relatives of the vertebrates. Their viruses may also reflect this transitional state. Yet, it is not known whether tunicate viruses are more closely related to vertebrate- or invertebrate-infecting viral lineages. We analysed primary and publicly available RNA libraries to extend the known diversity of tunicate-associated viruses and determine their relationship to viruses of other animals. We present evidence that influenza viruses, alphaviruses, and some mononegaviruses emerged prior to the evolution of vertebrates. We also show that the recombination of glycoproteins between different orders of RNA viruses, including between positive- and negative-sense viruses, may have shaped the evolution of multiple lineages. Our study reveals that some disease-causing RNA virus lineages were present in early chordates and highlights that the evolution of structural genes may be incongruent with that of the highly conserved RNA-dependent RNA polymerase.

microbiology↗

From a single sequence to evolutionary trajectories: protein language models capture the evolutionary potential of SARS-CoV-2 protein sequences

Protein language models (PLMs) capture features of protein three-dimensional structure from amino acid sequences alone, without requiring multiple sequence alignments (MSA). The concepts of grammar and semantics from natural language have the potential to capture functional properties of proteins. Here, we investigate how these representations enable assessment of variation due to mutation. Applied to SARS-CoV-2s spike protein using in silico deep mutational scanning (DMS) we demonstrate the PLM, ESM-2, has learned the sequence context within which variation occurs, capturing evolutionary constraint. This recapitulates what conventionally requires MSA data to predict. Unlike other state-of-the-art methods which require protein structures or multiple sequences for training, we show what can be accomplished using an unmodified pretrained PLM. We demonstrate that the grammaticality and semantic scores represent novel metrics. Applied to SARS-CoV-2 variants across the pandemic we show that ESM-2 representations encode the evolutionary history between variants, as well as the distinct nature of variants of concern upon their emergence, associated with shifts in receptor binding and antigenicity. PLM likelihoods can also identify epistatic interactions among sites in the protein. Our results here affirm that PLMs are broadly useful for variant-effect prediction, including unobserved changes, and can be applied to understand novel viral pathogens with the potential to be applied to any protein sequence, pathogen or otherwise.

bioinformatics↗

Mapping glycoprotein structure reveals defining events in the evolution of the Flaviviridae

Viral glycoproteins drive membrane fusion in enveloped viruses and determine host range, tissue tropism and pathogenesis. Despite their importance, there is a fragmentary understanding of glycoproteins within the Flaviviridae; for many species the glycoproteins have not yet been identified, for others, such as the hepaciviruses, the molecular mechanisms of membrane fusion remain uncharacterised. Here, we combine comprehensive phylogenetic analyses with systematic protein structure prediction to survey glycoproteins across the entire Flaviviridae. We discover class-II fusion systems, homologous to the orthoflavivirus E glycoprotein, in most species, including highly-divergent jingmenviruses and large genome flaviviruses. However, the E1E2 glycoproteins of the hepaci-, pegi- and pestiviruses are structurally distinct, may represent a novel class of fusion mechanism, and are strictly associated with infection of vertebrate hosts. By mapping glycoprotein distribution onto the underlying phylogeny we reveal a complex history of evolutionary events that have shaped the diverse virology and ecology of the Flaviviridae.

microbiology↗

A 39.8kb flavi-like virus uses a novel strategy for overcoming the RNA virus error threshold

It is commonly held that there is a fundamental relationship between genome size and error rate, manifest as a notional "error threshold" that sets an upper limit on genome sizes. The genome sizes of RNA viruses, which have intrinsically high mutation rates due to a lack of mechanisms for error correction, must therefore be small to avoid accumulating an excessive number of deleterious mutations that will ultimately lead to population extinction. The proposed exceptions to this evolutionary rule are RNA viruses from the order Nidovirales (such as coronaviruses) that encode an error correcting exonuclease, enabling them to reach genome lengths greater than 40kb. The recent discovery of large genome flavi-like viruses (Flaviviridae), which comprise genomes up to 27kb in length yet seemingly do not encode exonuclease domains, has led to the proposal that a proofreading mechanism is required to facilitate the expansion of RNA virus genomes above 30kb. Herein, we describe a 39.8kb flavi-like virus identified in a Haliclona sponge metatranscriptome that does not encode an exonuclease. Structural analysis revealed that this virus may have instead captured bacterial domains associated with nucleic acid metabolism that have not been previously found in RNA viruses. Phylogenetic analysis placed this virus as a divergent pesti-like lineage, such that we have provisionally termed it Maximus pesti-like virus. This virus represents the first instance of a flavi-like virus achieving a genome size comparable to that of the Nidovirales and demonstrates that RNA viruses have evolved multiple solutions to overcome the error threshold.

evolutionary biology↗

Evidence of a novel viral membranefusion mechanism shared by theHepaci, Pegi and Pestiviruses

Enveloped viruses encode specialised glycoproteins that mediate fusion of viral and host membranes. Discovery and understanding of the molecular mechanisms of fusion has been achieved through structural analyses of glycoproteins from many different viruses, and yet the fusion mechanisms of some viral genera remain unknown. We have employed systematic genome annotation and AlphaFold modelling to predict the structures of the E1E2 glycoproteins from sixty viral species in the Hepaci, Pegi and Pestivirus genera. Whilst the predicted structure of E2 varied widely, E1 exhibited a very consistent fold across genera, despite little or no homology at the sequence level. Critically, the structure of E1 is unlike any other known viral glycoprotein. This is the first evidence that the Hepaci, Pegi and Pestiviruses possess a common and novel membrane fusion mechanism. Comparison of E1E2 models from various species reveals recurrent features that are likely to be mechanistically important and sheds light on the evolution of membrane fusion in these viral genera. These findings provide new fundamental understanding of viral membrane fusion and are relevant to structure-guided vaccinology.

microbiology↗

Distantly related hepaciviruses share common entry factor, Claudin-1

Due to increased and broadened screening efforts, the last decade has seen a rapid expansion in the number of viral species classified into the Hepacivirus genus. Conserved genetic features of hepaciviruses suggest they have undergone specific adaptation and evolved to hijack similar host proteins for efficient propagation in the liver. Here, we developed pseudotyped viruses to elucidate the entry factors of GB virus-B (GBV-B), the first hepacivirus described in an animal, closely related to hepatitis C virus (HCV). GBV-B pseudotyped viruses (GBVBpp) were shown to be uniquely sensitive to the serum of tamarins infected with GBV-B, validating their usefulness as a surrogate for GBV-B entry studies. We screened GBVBpp infection of hepatoma cell lines CRISPR/Cas9-engineered to ablate expression of individual HCV receptors/entry factors and found that claudin-1 is essential for GBV-B infection, indicating GBV-B and HCV share a common entry factor. Our data suggest that claudin-1 facilitates HCV and GBV-B entry through distinct mechanisms since the former requires the first extracellular loop and the latter is reliant on the second extracellular loop. The implication of this sharing of claudin-1 as an entry factor between these two hepaciviruses on their tissue tropism and evolutionary relationships will be discussed. ImportanceHepatitis C virus (HCV) is a major public health burden; approximately 58 million individuals have chronic HCV infection which could lead to cirrhosis and liver cancer. To achieve the World Health Organisation target of eliminating hepatitis by 2030, new therapeutics and vaccines are needed. Understanding how HCV enters the cells will inform the design of new vaccines and treatments, targeting the first stage of HCV infection. However, the entry mechanism is complex and sparsely described. Studying the entry of related hepaciviruses will increase the knowledge of the molecular mechanisms of the first stages of HCV infection, such as the membrane fusion, and inform structure-guided HCV vaccine design; in this work we have identified a protein, Claudin-1, which facilitates the entry of HCV-related hepacivirus, but with a mechanism not described for HCV. Similar work on other hepaciviruses may unveil commonality of entry factors and possibly new mechanisms.

microbiology↗

Accurate viral genome reconstruction and host assignment with proximity-ligation sequencing

Viruses play crucial roles in the ecology of microbial communities, yet they remain relatively understudied in their native environments. Despite many advancements in high-throughput whole-genome sequencing (WGS), sequence assembly, and annotation of viruses, the reconstruction of full-length viral genomes directly from metagenomic sequencing is possible only for the most abundant phages and requires long-read sequencing technologies. Additionally, the prediction of their cellular hosts remains difficult from conventional metagenomic sequencing alone. To address these gaps in the field and to accelerate the study of viruses directly in their native microbiomes, we developed an end-to-end bioinformatics platform for viral genome reconstruction and host attribution from metagenomic data using proximity-ligation sequencing (i.e., Hi-C). We demonstrate the capabilities of the platform by recovering and characterizing the metavirome of a variety of metagenomes, including a fecal microbiome that has also been sequenced with accurate long reads, allowing for the assessment and benchmarking of the new methods. The platform can accurately extract numerous near-complete viral genomes even from highly fragmented short-read assemblies and can reliably predict their cellular hosts with minimal false positives. To our knowledge, this is the first software for performing these tasks. Being significantly cheaper than long-read sequencing of comparable depth, the incorporation of proximity-ligation sequencing in microbiome research shows promise to greatly accelerate future advancements in the field.

genomics↗

Accounting for age-of-onset and family history improves power in genome-wide association studies

Genome-wide association studies (GWAS) have revolutionized human genetics, allowing researchers to identify thousands of disease-related genes and possible drug targets. However, case-control status does not account for the fact that not all controls may have lived through their period of risk for the disorder of interest. This can be quantified by examining the age-of-onset distribution and the age of the controls or the age-of-onset for cases. The age-of-onset distribution may also depend on information such as sex and birth year. In addition, family history is not routinely included in the assessment of control status. Here we present LT-FH++, an extension of the liability threshold model conditioned on family history (LT-FH), that jointly accounts for age-of-onset and sex, as well as family history. Using simulations, we show that, when family history and the age-of-onset distribution are available, the proposed approach yields large power gains over both LT-FH and genome-wide association study by proxy (GWAX). We applied our method to four psychiatric disorders available in the iPSYCH data, and to mortality in the UK Biobank, finding 20 genome-wide significant associations with LT-FH++, compared to 10 for LT-FH and 8 for a standard case-control GWAS. As more genetic data with linked electronic health records become available to researchers, we expect methods that account for additional health information, such as LT-FH++, to become even more beneficial.

bioinformatics↗

Characterisation of B.1.1.7 and Pangolin coronavirus spike provides insights on the evolutionary trajectory of SARS-CoV-2

The recent emergence of SARS-CoV-2 variants with increased transmission, pathogenesis and immune resistance has jeopardised the global response to the COVID-19 pandemic. Determining the fundamental biology of viral variants and understanding their evolutionary trajectories will guide current mitigation measures, future genetic surveillance and vaccination strategies. Here we examine virus entry by the B.1.1.7 lineage, commonly referred to as the UK/Kent variant. Pseudovirus infection of model cell lines demonstrate that B.1.1.7 entry is enhanced relative to the Wuhan-Hu-1 reference strain, particularly under low expression of receptor ACE2. Moreover, the entry characteristics of B.1.1.7 were distinct from that of its predecessor strain containing the D614G mutation. These data suggest evolutionary tuning of spike protein function. Additionally, we found that amino acid deletions within the N-terminal domain (NTD) of spike were important for efficient entry by B.1.1.7. The NTD is a hotspot of diversity across sarbecoviruses, therefore, we further investigated this region by examining the entry of closely related CoVs. Surprisingly, Pangolin CoV spike entry was 50-100 fold enhanced relative to SARS-CoV-2; suggesting there may be evolutionary pathways by which SARS-CoV-2 may further optimise entry. Swapping the NTD between Pangolin CoV and SARS-CoV-2 demonstrates that changes in this region alone have the capacity to enhance virus entry. Thus, the NTD plays a hitherto unrecognised role in modulating spike activity, warranting further investigation and surveillance of NTD mutations.

microbiology↗

Leveraging both individual-level genetic data and GWAS summary statistics increases polygenic prediction

The accuracy of polygenic risk scores (PRSs) to predict complex diseases increases with the training sample size. PRSs are generally derived based on summary statistics from large meta-analyses of multiple genome-wide association studies (GWAS). However, it is now common for researchers to have access to large individual-level data as well, such as the UK biobank data. To the best of our knowledge, it has not yet been explored how to best combine both types of data (summary statistics and individual-level data) to optimize polygenic prediction. The most widely used approach to combine data is the meta-analysis of GWAS summary statistics (Meta-GWAS), but we show that it does not always provide the most accurate PRS. Through simulations and using twelve real case-control and quantitative traits from both iPSYCH and UK Biobank along with external GWAS summary statistics, we compare Meta-GWAS with two alternative data-combining approaches, stacked clumping and thresholding (SCT) and Meta-PRS. We find that, when large individual-level data is available, the linear combination of PRSs (Meta-PRS) is both a simple alternative to Meta-GWAS and often more accurate.

genetics↗

An Entropic Safety Catch Controls Hepatitis C Virus Entry and Antibody Resistance.

E1 and E2 (E1E2), the entry proteins of Hepatitis C Virus (HCV), are unlike that of any other virus yet described, and the detailed molecular mechanisms of HCV entry/fusion remain unknown. Hypervariable region-1 (HVR-1) of E2 is a putative intrinsically disordered protein tail. Here, we demonstrate that HVR-1 has an autoinhibitory function that suppresses the activity of E1E2 on free virions; this is dependent on its conformational entropy. Crucially, to allow entry, this mechanism is turned off by host receptor interactions at the cell surface. Thus, HVR-1 is akin to a safety catch on E1E2 activity. Mutations that reduce conformational entropy in HVR-1, or genetic deletion of HVR-1, turn off the safety catch to generate hyper-reactive HCV that exhibits enhanced virus entry but is thermally unstable and acutely sensitive to neutralising antibodies. Therefore, the HVR-1 safety catch controls the efficiency of virus entry and maintains resistance to neutralising antibodies.

molecular biology↗