Biology subjects

Cowton, V. M.

Publications and source records attributed to Cowton, V. M..

4 recordsLinked to original sources

bioRxiv2025

SARS-CoV-2 envelope protein induces LC3 lipidation via the V-ATPase-ATG16L1 axis

Coronaviruses encode envelope (E), a structural component of the virion that is important for assembly and egress. E has proton channel activity that prevents premature rearrangement of the spike glycoprotein as virions encounter acidic compartments as they exit the cell. How infected cells respond to this pH disruption during coronavirus infection is unknown. Here we show that SARS-CoV-2 E ion channel activity triggers the proton pump V-ATPases to recruit the ATG16L1 complex during infection. This results in ATG8 molecules such as LC3B decorating perturbed compartments. This recruitment of autophagy machinery does not inhibit viral replication, rather SARS-CoV-2 exploits this response. Inhibition of the V-ATPase/ATG16L1 interaction using the Salmonella effector SopF inhibits SARS-CoV-2 replication. Careful distinction between use of the autophagic machinery from canonical macroautophagy is required in order to better understand coronavirus replication and for rational targeting of any potential host-directed therapies.

cell biology↗

bioRxiv2022

Enhanced innate immune suppression by SARS-CoV-2 Omicron subvariants BA.4 and BA.5

SARS-CoV-2 adaptation to humans is evidenced by the emergence of variants of concern (VOCs) with distinct genotypes and phenotypes that facilitate immune escape and enhance transmission frequency. Most recently Omicron subvariants have emerged with heavily mutated spike proteins which facilitate re-infection of immune populations through extensive antibody escape driving replacement of previously-dominant VOCs Alpha and Delta. Interestingly, Omicron is the first VOC to produce distinct subvariants. Here, we demonstrate that later Omicron subvariants, particularly BA.4 and BA.5, have evolved an enhanced capacity to suppress human innate immunity when compared to earliest subvariants BA.1 and BA.2. We find that, like previously dominant VOCs, later Omicron subvariants tend to increase expression of viral innate immune antagonists Orf6 and nucleocapsid. We show Orf6 to be a key contributor to enhanced innate immune suppression during epithelial replication by BA.5 and Alpha, reducing innate immune signaling through IRF3 and STAT1. Convergent VOC evolution of enhanced innate immune antagonist expression suggests common pathways of adaptation to humans and links VOC, and in particular Omicron subvariant, dominance to improved innate immune evasion.

microbiology↗

bioRxiv2021

Mutations that adapt SARS-CoV-2 to mustelid hosts do not increase fitness in the human airway.

SARS-CoV-2 has a broad mammalian species tropism infecting humans, cats, dogs and farmed mink. Since the start of the 2019 pandemic several reverse zoonotic outbreaks of SARS-CoV-2 have occurred in mink, one of which reinfected humans and caused a cluster of infections in Denmark. Here we investigate the molecular basis of mink and ferret adaptation and demonstrate the spike mutations Y453F, F486L, and N501T all specifically adapt SARS-CoV-2 to use mustelid ACE2. Furthermore, we risk assess these mutations and conclude mink-adapted viruses are unlikely to pose an increased threat to humans, as Y453F attenuates the virus replication in human cells and all 3 mink-adaptations have minimal antigenic impact. Finally, we show that certain SARS-CoV-2 variants emerging from circulation in humans may naturally have a greater propensity to infect mustelid hosts and therefore these species should continue to be surveyed for reverse zoonotic infections.

microbiology↗

bioRxiv2018

Interferon lambda 4 impacts broadly on hepatitis C virus diversity.

Type III interferons (IFN-{lambda}) are part of the innate immune response to hepatitis C virus (HCV) infection however the specific role of IFN-{lambda}4 and the nature of the viral adaption to this pressure have not been defined. Here we use paired genome-wide human and viral genetic data in 485 patients infected with HCV genotype 3a to explore the role of IFN-{lambda}4 on HCV evolution during chronic infection. We show that genetic variations within the host IFNL4 locus have a broad and systematic impact on HCV amino acid diversity. We also demonstrate that this impact is larger in patients producing a more active form of IFN-{lambda}4 protein compared to the less active form. A similar observation was noted for viral load. We conclude that IFN-{lambda}4 protein is a likely causal agent driving widespread HCV amino acid changes and associated with viral load and possibly other clinical and biological outcomes of HCV infection.

genomics↗