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Hoffmann, B.

Publications and source records attributed to Hoffmann, B..

At least 19 recordsLinked to original sources

It happened again - emergence of a Shamonda-like orthobunyavirus in Central Europe, 2026

Since mid-June 2026, an acute, non-fatal syndrome with high herd morbidity, reduced milk yield, diarrhea, fever and lethargy affected dairy cattle in southern Germany and Switzerland. Major viral pathogens were excluded. Pan-Simbuvirus PCR first detected an orthobunyavirus, subsequently confirmed by metagenomic sequencing, which enabled recovery of a complete "Shamonda-like" genome. One sentence summary lineMore than a decade after the emergence of Schmallenberg virus in 2011, a novel "Shamonda-like" orthobunyavirus of the Simbu serogroup has now emerged in Central Europe.

microbiology↗

Translational profiling uncovers a tonoplast sugar transporter essential for vascular system development and cell wall composition

The inflorescence stem of Arabidopsis thaliana is a powerful model to study vascular development and carbon allocation, yet the translational landscape underlying xylem differentiation remains poorly defined. Here, we address this gap using tissue-specific Translating Ribosome Affinity Purification sequencing (TRAP-seq) to resolve the translatomes of xylem vessels, xylem parenchyma, and interfascicular fibers. We show that the very early stage of metaxylem differentiation involves coordinated activation of primary metabolism, plastid functions, and cell wall biosynthesis, supporting the metabolic demands of secondary wall formation. Xylem parenchyma displays enrichment in hormone signaling, stress, and immune pathways, consistent with a role in integrating environmental and metabolic cues. Interfascicular fibers exhibit increased translation of ribosomal proteins and spliceosome components, pointing to high translational activity and a role for alternative splicing during late development and programmed cell death. We further identify the tonoplast sugar transporter SUGAR WILL EVENTUALLY BE EXPORTED TRANSPORTER 2 (SWEET2) as a key regulator of stem radial growth. Preferentially translated in early stage of metaxylem differentiation, SWEET2 acts as a rate-limiting component of vacuolar sugar exchange, controlling cytosolic hexose availability for secondary wall biosynthesis. By contrast, SWEET16 and SWEET17 exert more specialized, tissue-specific functions. Together, our findings establish subcellular sugar partitioning as a central determinant of vascular development and highlight the power of translatome profiling.

plant biology↗

Buffaloed in Brandenburg: Germany's first Brush with Foot-and-Mouth Disease after four Decades of Freedom

Foot-and-mouth disease (FMD) virus is one of the most feared and most consequential pathogens of livestock worldwide. It can be spread rapidly by the transboundary movement of animals, animal products and byproducts. In January 2025, Germany detected its first FMD outbreak since 1988 in extensively reared water buffalo on a small farm in the state of Brandenburg, directly outside Berlin, the federal capital. Immediate control measures including a standstill for movements of susceptible animals and pre-emptive culling were implemented by the veterinary authorities. Whole-genome sequencing identified the virus as serotype O, topotype ME-SA, lineage SA-2018 and revealed extensive recombination, but cross-neutralization assays suggested good heterologous protection by an O/PanAsia-2 vaccine strain. Epidemiological back-calculation placed the time of virus introduction in late December 2024. Although the entry route remains unresolved, human-associated introduction is most likely. Network analysis revealed minimal farm connectivity, and simulations predicted low potential for onward transmission, which is consistent with the outbreak being ultimately restricted to a single herd. This event underscores the constant and unpredictable risk of introduction of the virus. Early detection through increased awareness and comprehensive differential diagnostics as well as the international collaboration of veterinary services, laboratories and experts are essential in the face of the global presence of FMD.

microbiology↗

A century-old museum sample reveals abandavirus with modern day presence in northernEuropean bats

Ancient genome sequences provide invaluable insights into the origin and evolution of viral pathogens, offering a broader temporal perspective that extends well beyond the limited timespan of clinical data, which typically covers at most a few decades. Whereas ancient viral DNA is relatively frequently recovered, ancient viral RNA genomes are scarce due to the fragile nature of RNA molecules. In this study, we explored the feasibility of detecting ancient viral RNA in ethanol-preserved bat samples from a museum collection. We not only detected viral genome fragments but also recovered the coding-complete genome of a bandavirus (species Bandavirus zwieselense, family Phenuiviridae, order Hareavirales, class Bunyaviricetes) from a Common pipistrelle (Pipistrellus pipistrellus) bat collected in northern Germany in 1919. To investigate the modern distribution of Bandavirus zwieselense, we screened bat organs collected in Germany and the Netherlands via RT-qPCR, identifying modern counterparts in nine Common Pipistrelle (P. pipistrellus) bats (collected between 2010 and 2018), and one Serotine bat (Eptesicus serotinus, collected in 1999). The resulting genomic data enabled us to map phylogenetic relationships within this previously uncharacterized virus species (Bandavirus zwieselense) and estimate the timeframe for the most recent common ancestor. Additionally, we performed functional analysis of the S segment encoded nonstructural (NSs) protein of Bandavirus zwieselense in human HEK-293T cells, demonstrating its ability to block interferon induction, a characteristic also observed in the related human-pathogenic Severe fever with thrombocytopenia syndrome virus (SFTSV, species Bandavirus dabieense). This study demonstrates the feasibility of recovering and characterizing viral genomes from ethanol-preserved ancient RNA material, underscoring the significant potential of museum collections to contribute to the understanding of RNA virus evolution.

microbiology↗

Experimental BTV-3 and BTV-8 infection of Culicoides sonorensis biting midges

BTV-3 emerged in the Netherlands in 2023 and spread rapidly to neighboring countries. Compared to the BTV-8 outbreak in 2006, the course of the BTV-3 epizootic is more severe. Experimental infection of laboratory-reared Culicoides sonorensis midges showed a slightly higher replication rate of BTV-3 than of BTV-8. One sentence summary lineWe experimentally infected laboratory-reared Culicoides sonorensis biting midges with bluetongue virus (BTV) serotypes 3 and 8 using virus-containing blood meal and found slightly higher replication rates of BTV-3.

microbiology↗

A molecular representation to identify isofunctional molecules

The challenges of drug discovery from hit identification to clinical development sometimes involve addressing scaffold hopping issues, in order to optimize biological activity or ADME properties, improve selectivity or mitigate toxicology concerns of a drug candidate, not to mention intellectual property reasons. Docking is usually viewed as the method of choice for identification of isofunctional molecules, i.e. highly dissimilar molecules that share common binding modes with a protein target. However, in cases where the protein structure has low resolution or is unknown, docking may not be suitable. In such cases, ligand-based approaches offer promise but are often inadequate to handle large-step scaffold hopping, because they usually rely on the molecular structure. Therefore, we propose the Interaction Fingerprints Profile (IFPP), a molecular representation that captures molecules binding modes based on docking experiments against a panel of diverse high-quality protein structures. Evaluation on the Large-Hops (LH) benchmark demonstrates the utility of IFPP for identification of isofunctional molecules. Nevertheless, computation of IFPPs is expensive, which limits the scalability for screening very large molecular libraries. We propose to overcome this limitation by leveraging Metric Learning approaches, allowing fast estimation of molecules IFPP similarities, thus providing an efficient pre-screening strategy applicable to very large molecular libraries. Overall, our results suggest that IFPP provides an interesting and complementary tool alongside existing methods, in order to address challenging scaffold hopping problems effectively in drug discovery.

bioinformatics↗

Emergence of bluetongue virus serotype 3 in western Germany, October 2023, and ad-hoc monitoring in Culicoides biting midges

Bluetongue virus serotype 3 emerged in October 2023 in Germany, where Schmallenberg virus is enzootic. BTV-3 was detected in a pool of Culicoides biting midges at the same time as infections were reported from ruminants. Schmallenberg virus was frequently found in vector pools, reflecting the epidemiological situation. One sentence summary lineCoinciding with the emergence and low-level circulation of bluetongue virus serotype 3 in ruminants in Germany in October 2023, the virus was detected in a pool of Culicoides biting midges of the Obsoletus Group, while enzootic Schmallenberg virus was found in numerous midge pools.

microbiology↗

Advancing Drug-Target Interactions Prediction: Leveraging a Large-Scale Dataset with a Rapid and Robust Chemogenomic Algorithm.

Drug-target interactions (DTIs) prediction algorithms are used are various stages of the drug discovery process. In this context, specific problems such as de-orphanization of a new therapeutic target, or target identification of a drug candidate arising from phenotypic screens require large-scale predictions across the protein and molecule spaces. DTI prediction heavily relies on supervised learning algorithms that use known DTIs to learn associations between molecule and protein features, allowing for the prediction of new interactions based on learned patterns. The algorithms must be broadly applicable to enable reliable predictions, even in regions of the protein or molecule spaces where data may be scarce. In this paper, we address two key challenges to fulfil these goals: building large, high-quality training datasets and designing prediction methods that can scale, in order to be trained on such large datasets. First, we introduce LCIdb, a curated, large-sized dataset of DTIs, offering extensive coverage of both the molecule and druggable protein spaces. Notably, LCIdb contains a much higher number of molecules than publicly available benchmarks, expanding coverage of the molecule space. Second, we propose Komet (Kronecker Optimized METhod), a DTI prediction pipeline designed for scalability without compromising performance. Komet leverages a three-step framework, incorporating efficient computation choices tailored for large datasets and involving the Nystrom approximation. Specifically, Komet employs a Kronecker interaction module for (molecule, protein) pairs, which efficiently captures determinants in DTIs, and whose structure allows for reduced computational complexity and quasi-Newton optimization, ensuring that the model can handle large training sets, without compromising on performance. Our method is implemented in open-source software, leveraging GPU parallel computation for efficiency. We demonstrate the interest of our pipeline on various datasets, showing that Komet displays superior scalability and prediction performance compared to state-of-the-art deep learning approaches. Additionally, we illustrate the generalization properties of Komet by showing its performance on an external dataset, and on the publicly available[L][H] benchmark designed for scaffold hopping problems. Komet is available open source at https://komet.readthedocs.io and all datasets, including LCIdb, can be found at https://zenodo.org/records/10731712.

bioinformatics↗

A Phased, Chromosome-scale Genome for Malus domestica 'WA 38'

Genome sequencing for agriculturally important Rosaceous crops has made rapid progress both in completeness and annotation quality. Whole genome sequence and annotation gives breeders, researchers, and growers information about cultivar specific traits such as fruit quality, disease resistance, and informs strategies to enhance postharvest storage. Here we present a haplotype-phased, chromosomal level genome of Malus domestica, WA 38, a new apple cultivar released to market in 2017 as Cosmic Crisp (R). Using both short and long read sequencing data with a k-mer based approach, chromosomes originating from each parent were assembled and segregated. This is the first pome fruit genome fully phased into parental haplotypes in which chromosomes from each parent are identified and separated into their unique, respective haplomes. The two haplome assemblies, Honeycrisp originated HapA and Enterprise originated HapB, are about 650 Megabases each, and both have a BUSCO score of 98.7% complete. A total of 53,028 and 54,235 genes were annotated from HapA and HapB, respectively. Additionally, we provide genome-scale comparisons to Gala, Honeycrisp, and other relevant cultivars highlighting major differences in genome structure and gene family circumscription. This assembly and annotation was done in collaboration with the American Campus Tree Genomes project that includes WA 38 (Washington State University), dAnjou pear (Auburn University), and many more. To ensure transparency, reproducibility, and applicability for any genome project, our genome assembly and annotation workflow is recorded in detail and shared under a public GitLab repository. All software is containerized, offering a simple implementation of the workflow.

genomics↗

Elastomeric Pillar Cages Modulate Actomyosin Contractility of Epithelial Microtissues by Substrate Stiffness and Topography

Cell contractility regulates epithelial tissue geometry development and homeostasis. The underlying mechanobiological regulation circuits are poorly understood and experimentally challenging. We developed an elastomeric pillar cage (EPC) array to quantify cell contractility as a mechanoresponse of epithelial microtissues to substrate stiffness and topography. The spatially confined EPC geometry consisted of 24 circularly arranged slender pillars (1.2 MPa, height: 50 m, diameter: 10 m, distance: 5 m). These high-aspect-ratio pillars were confined at both ends by planar substrates with different stiffness (0.15 - 1.2 MPa). Analytical modeling and finite elements simulation retrieved cell forces from pillar displacements. For evaluation, highly contractile myofibroblasts and cardiomyocytes were assessed to demonstrate that the EPC device can resolve static and dynamic cellular force modes. Human breast (MCF10A) and skin (HaCaT) cells grew as adherence junction-stabilized 3D microtissues within the EPC geometry. Planar substrate areas triggered the spread of monolayered clusters with substrate stiffness-dependent actin stress fiber (SF)-formation and substantial single-cell actomyosin contractility (150 - 200 nN). Within same continuous microtissues, the pillar-ring topography induced bilayered cell tube growth. Here, low effective pillar stiffness overwrote local substrate stiffness sensing and induced SF-lacking roundish cell shapes with extremely low cortical actin tension (11 - 15 nN). This work introduced a versatile biophysical tool to explore mechanobiological regulation circuits driving low- and high-tensional states in developing and homeostatic microtissues. EPC arrays facilitate simultaneously analyzing the impact of planar substrate stiffness and topography on microtissue contractility hence microtissue geometry and function.

cell biology↗

The role of pneumococcal extracellular vesicles on the pathophysiology of the kidney disease Hemolytic Uremic Syndrome

Streptococcus pneumoniae-induced hemolytic uremic syndrome (Sp-HUS) is a kidney disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. This disease is frequently underdiagnosed and its pathophysiology is poorly understood. In this work, we compared clinical strains, isolated from infant Sp-HUS patients, to a reference pathogenic strain D39, for host cytotoxicity and further explored the role of Sp-derived extracellular vesicles (EVs) in the pathogenesis of a HUS infection. In comparison with the WT strain, pneumococcal HUS strains caused significant lysis of human erythrocytes and increased the release of hydrogen peroxide. Isolated Sp-HUS EVs were characterized by performing dynamic light-scattering microscopy and proteomic analysis. Sp-HUS strain released EVs at a constant concentration during growth, yet the size of the EVs varied and several subpopulations emerged at later time points. The cargo of the Sp-HUS EVs included several virulence factors at high abundance, i.e., the ribosomal subunit assembly factor BipA, the Pneumococcal Surface Protein A (PspA), the lytic enzyme LytC, several sugar utilization and fatty acid synthesis proteins. Sp-HUS EVs strongly downregulated the expression of the endothelial surface marker PECAM-1 and were internalized by human endothelial cells. Sp-HUS EVs elicited the release of pro-inflammatory cytokines (IL-1{beta}, IL-6) and chemokines (CCL2, CCL3, CXCL1) by human monocytes. These findings shed new light on the overall function of Sp-EVs, in the scope of infection-mediated HUS, and suggest new avenues of research for exploring the usefulness of Sp-EVs as therapeutic and diagnostic targets. ImportanceStreptococcus pneumoniae is a life-threatening human pathogen associated with severe illnesses in the upper respiratory tract. Disseminated infections also occur, as the kidney disease hemolytic uremic syndrome. Even though vaccination is available, this pathogen is responsible for a worldwide high mortality rate, especially among children from least developed countries, where vaccination strategies are poor or inexistent. It is estimated that 30% of invasive pneumococcal diseases are caused by antibiotic resistant bacteria, leading to the classification of "serious threat" by the World Health Organization. In order to prevent cases of severe illness, investigation in the direction of new vaccine candidates is of upmost importance. Pneumococcal extracellular vesicles pose as ideal candidates for a serotype-independent vaccine formulation. To this purpose, the aspects of vesicle formation, cargo allocation and function need to be understood in detail. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=159 SRC="FIGDIR/small/526387v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@1f5faeborg.highwire.dtl.DTLVardef@2c6176org.highwire.dtl.DTLVardef@1b29245org.highwire.dtl.DTLVardef@a119ea_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

Impairment of sugar transport in the vascular system acts on nitrogen remobilisation and nitrogen use efficiency in Arabidopsis.

The carbon (C) and nitrogen (N) metabolisms have long been known to be coupled, and this is required for adjusting nitrogen use efficiency. Despite this intricate relationship, it is still unclear how a deregulation of sugar transport impacts N allocation. Here we investigated, in Arabidopsis, the consequences of the simultaneous downregulation of the genes coding for the sugar transporters SWEET11, SWEET12, SWEET16, and SWEET17 genes on various anatomical and physiological traits ranging from the stems vascular system development, plant biomass production, seed yield, and N remobilisation and use efficiency. Our results show that intracellular sugar exchanges mediated by SWEET16 and SWEET17 proteins specifically impact the vascular development but do not play a significant role in the distribution of N. Most importantly, we showed that the double mutant swt11swt12, which is also impacted in the vascular development, displays an improved nitrogen use efficiency and nitrogen remobilisation to the seeds. In addition, a significant negative correlation between sugar and amino acids contents and the inflorescence stem radial growth exists, highlighting the complex interaction between the maintenance of C/N homeostasis and the inflorescence stem development. Our results thus deepen the link between sugar transport, C/N allocation and vascular system development. HighlightThe disruption of genes coding for SWEET11 and SWEET12 sugar transporters negatively impacts the stem development but improves the plant nitrogen use efficiency and nitrogen remobilisation to the seeds.

plant biology↗

Selectively expressed RNA molecules: a new dimension infunctionalized cell targeting

Exact targeting of specific mammalian cell types or diseased cells is one of the most urgently needed prerequisites for a new generation of potent pharmaceuticals. Different approaches have been pursued, failing mainly due to a lack of specific surface markers in most cases. Developing a completely novel RNA-based methodology, we can now ensure exact cell targeting and simultaneously combine this with selective expression of effector proteins, thereby functionalization of the target cell for therapy, diagnostics or cell steering. The specific combination of the molecular properties of antisense technology and mRNA therapy with functional RNA secondary structures allowed us to develop selectively expressed RNA molecules for medical applications. These so-called seRNAs remain inactive in non-target cells and are only activated by partial degradation to induce translation in preselected cell types of interest. Cell type specificity and type of functionalization are easily adaptable based on a simple modular system. In proof of concept in vitro and in vivo studies we used seRNAs as a highly selective platform technology for powerful glioblastoma cancer cell targeting and significantly reduce brain tumors of mice without detectable side effects with just a single treatment within days. Our data open up new potential avenues for the efficient treatment of various cancers and other human diseases.

cell biology↗

The spike gene is a major determinant for the SARS-CoV-2 Omicron-BA.1 phenotype

Variant of concern (VOC) Omicron-BA1 has achieved global predominance in early 2022. Therefore, surveillance and comprehensive characterization of Omicron-BA.1 in advanced primary cell culture systems and multiple animal models is urgently needed. Here, we characterized Omicron-BA.1 and recombinant Omicron-BA.1 spike gene mutants in comparison with VOC Delta in well-differentiated primary human nasal and bronchial epithelial cells in vitro, followed by in vivo fitness characterization in naive hamsters, ferrets and hACE2-expressing mice, and in immunized hACE2-mice. We demonstrate a spike-mediated enhancement of early replication of Omicron-BA.1 in nasal epithelial cultures, but limited replication in bronchial epithelial cultures. In Syrian hamsters, Delta showed dominance over Omicron-BA.1 and in ferrets, Omicron-BA.1 infection was abortive. In mice expressing the authentic hACE2-receptor, Delta and a Delta spike clone also showed dominance over Omicron-BA.1 and an Omicron-BA.1 spike clone, respectively. Interestingly, in naive K18-hACE2 mice, we observed Delta spike-mediated increased replication and pathogenicity and Omicron-BA.1 spike-mediated reduced replication and pathogenicity, suggesting that the spike gene is a major determinant of both Delta and Omicron-BA.1 replication and pathogenicity. Finally, the Omicron-BA.1 spike clone was less well controlled by mRNA-vaccination in K18-hACE2-mice and became more competitive compared to the progenitor and Delta spike clones, suggesting that spike gene-mediated immune evasion is another important factor that led to Omicron-BA.1 dominance.

microbiology↗

Enhanced fitness of SARS-CoV-2 variant of concern B.1.1.7, but not B.1.351, in animal models

Emerging variants of concern (VOCs) drive the SARS-CoV-2 pandemic. We assessed VOC B.1.1.7, now prevalent in several countries, and VOC B.1.351, representing the greatest threat to populations with immunity to the early SARS-CoV-2 progenitors. B.1.1.7 showed a clear fitness advantage over the progenitor variant (wt-S614G) in ferrets and two mouse models, where the substitutions in the spike glycoprotein were major drivers for fitness advantage. In the "superspreader" hamster model, B.1.1.7 and wt-S614G had comparable fitness, whereas B.1.351 was outcompeted. The VOCs had similar replication kinetics as compared to wt-S614G in human airway epithelial cultures. Our study highlights the importance of using multiple models for complete fitness characterization of VOCs and demonstrates adaptation of B.1.1.7 towards increased upper respiratory tract replication and enhanced transmission in vivo. Summary sentenceB.1.1.7 VOC outcompetes progenitor SARS-CoV-2 in upper respiratory tract replication competition in vivo.

microbiology↗

Targeted delivery of a phosphoinositide 3-kinase γ inhibitor to restore organ function in sepsis through dye-functionalized lipid nanocarriers

Jaundice, the clinical hallmark of infection-associated liver dysfunction, reflects altered membrane organization of the canalicular pole of hepatocytes and portends poor outcomes. Mice lacking phosphoinositide 3-kinase-{gamma} (PI3K{gamma}) are protected against membrane disintegration and hepatic excretory dysfunction. However, they exhibit a severe immune defect that hinders neutrophil recruitment to sites of infection. To exploit the therapeutic potential of PI3K{gamma} inhibition in sepsis, a targeted approach to deliver drugs to hepatic parenchymal cells without compromising other cells, in particular immune cells, seems warranted. Here we demonstrate that nanocarriers functionalized through DY-635, a fluorescent polymethine dye and a ligand of organic anion transporters can selectively deliver therapeutics to hepatic parenchymal cells. Applying this strategy to a murine model of sepsis, we observed PI3K{gamma}-dependent restoration of biliary canalicular architecture, maintained excretory liver function, and improved survival without impairing host defense mechanisms. This strategy carries the potential to expand targeted nanomedicines to disease entities with systemic inflammation and concomitantly impaired barrier functionality. One-Sentence SummaryDye-functionalized liposomes allow delivery of a PI3K{gamma} inhibitor to hepatocytes to resolve sepsis-related liver failure without off-target effects on immunity. Graphical AbstractTargeting PI3K{gamma} in hepatocytes by dye-functionalized liposomes to resolve sepsis-related liver failure without off-target effects on immunity. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=178 SRC="FIGDIR/small/427305v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@d52fdeorg.highwire.dtl.DTLVardef@39bf3aorg.highwire.dtl.DTLVardef@13999c7org.highwire.dtl.DTLVardef@9edfa0_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

Hexose fluxes, mediated by vacuolar SWEET transporters, are important for xylem development in the inflorescence stem of Arabidopsis thaliana.

In higher plants, the development of the vascular system is controlled by a complex network of transcription factors. However, how nutrient availability in the vascular cells affects their development remains to be addressed. At the cellular level, cytosolic sugar availability is regulated mainly by sugar exchanges at the tonoplast through active and/or facilitated transport. In Arabidopsis thaliana, among the tonoplastic transporters, SWEET16 and SWEET17 genes have been previously localized in the vascular system. Here, using a reverse genetic approach, we propose that sugar exchanges at the tonoplast, regulated by SWEET16, are important for xylem cell division as revealed in particular by the decreased number of xylem cells in the swt16 mutant and the expression of SWEET16 at the procambium-xylem boundary. In addition, we demonstrate that transport of hexoses mediated by SWEET16 and/or SWEET17 is required to sustain the formation of the xylem secondary cell wall. This result is in line with a defect in the xylem cell wall composition as measured by FTIR in the swt16swt17 double mutant and by upregulation of several genes involved in secondary cell wall synthesis. Our work therefore supports a model in which xylem development is partially dependent on the exchange of hexoses at the tonoplast of xylem-forming cells.

plant biology↗

SARS-CoV-2 spike D614G variant confers enhanced replication and transmissibility

During the evolution of SARS-CoV-2 in humans a D614G substitution in the spike (S) protein emerged and became the predominant circulating variant (S-614G) of the COVID-19 pandemic1. However, whether the increasing prevalence of the S-614G variant represents a fitness advantage that improves replication and/or transmission in humans or is merely due to founder effects remains elusive. Here, we generated isogenic SARS-CoV-2 variants and demonstrate that the S-614G variant has (i) enhanced binding to human ACE2, (ii) increased replication in primary human bronchial and nasal airway epithelial cultures as well as in a novel human ACE2 knock-in mouse model, and (iii) markedly increased replication and transmissibility in hamster and ferret models of SARS-CoV-2 infection. Collectively, our data show that while the S-614G substitution results in subtle increases in binding and replication in vitro, it provides a real competitive advantage in vivo, particularly during the transmission bottle neck, providing an explanation for the global predominance of S-614G variant among the SARS-CoV-2 viruses currently circulating.

microbiology↗