Biology subjects

Goodfellow, I. G.

Publications and source records attributed to Goodfellow, I. G..

3 recordsLinked to original sources

bioRxiv2018

Central carbon metabolism is an intrinsic factor for optimal replication of a norovirus

The metabolic pathways of central carbon metabolism, glycolysis and oxidative phosphorylation (OXPHOS), are important host factors that determine the outcome of viral infections and can therefore be manipulated by some viruses to favor infection. However, mechanisms of metabolic modulation and their effects on viral replication vary widely. Herein, we present the first metabolomics profile of norovirus-infected cells, which revealed increases in glycolysis, OXPHOS, and the pentose phosphate pathway (PPP) during murine norovirus infection. Inhibiting glycolysis with 2-deoxyglucose (2DG) in transformed and primary macrophages revealed that host cell metabolism is an important factor for optimal murine norovirus (MNV) infection. 2DG affected an early stage in the viral life cycle after viral uptake and capsid uncoating, leading to decreased levels of viral protein translation and viral RNA replication. The requirement of central carbon metabolism was specific for MNV (but not astrovirus) infection, independent of the Type I interferon antiviral response, and unlikely to be due to a lack of host cell nucleotide synthesis. MNV infection increased activation of the protein kinase Akt, but not AMPK, two master regulators of cellular metabolism, suggesting Akt signaling may play a role in upregulating central carbon metabolism during norovirus infection. In conclusion, our findings suggest that the metabolic state of target cells is an intrinsic host factor that determines the extent of norovirus replication and implicates metabolism as a virulence determinant. They further implicate cellular metabolism as a novel therapeutic target for norovirus infections and improvements of current human norovirus culture systems.\n\nIMPORTANCEViruses depend on the host cells they infect to provide the machinery and substrates for replication. Host cells are highly dynamic systems that can alter their intracellular environment and metabolic behavior, which may be helpful or inhibitory for an infecting virus. In this study, we show that macrophages, a target cell of murine norovirus (MNV), increase central carbon metabolism upon viral infection, which is important for early steps in MNV infection. Human noroviruses (hNoV) are a major cause of gastroenteritis globally, causing enormous morbidity and economic burden. Currently, no effective antivirals or vaccines exist for hNoV, mainly due to the lack of high efficiency in vitro culture models for their study. Thus, insights gained from the MNV model may reveal aspects of host cell metabolism that can be targeted for improving hNoV cell culture systems and for developing effective antiviral therapies.

microbiology↗

bioRxiv2018

Calicivirus VP2 forms a portal to mediate endosome escape

To initiate the infectious process, many viruses enter their host cells by triggering endocytosis following receptor engagement. The mechanism by which non-enveloped viruses, such as the caliciviruses, escape the endosome is however poorly understood. The Caliciviridae include many important human and animal pathogens, most notably norovirus, the cause of winter vomiting disease. Here we show that VP2, a minor capsid protein encoded by all caliciviruses, forms a large portal assembly at a unique three-fold symmetry axis following receptor engagement. This feature surrounds an open pore in the capsid shell. We hypothesise that the VP2 portal complex is the means by which the virus escapes the endosome, pene-trating the endosomal membrane to release the viral genome into the cytoplasm. Cryogenic electron microscopy (cryoEM) and asymmetric reconstruction were used to investigate structural changes in the capsid of feline calicivirus (FCV) that occur when the virus binds to its cellular receptor junctional adhesion molecule-A (fJAM-A). Near atomic-resolution structures were calculated for the native virion alone and decorated with soluble receptor fragments. We present atomic models of the major capsid protein VP1 in the presence and absence of fJAM-A, revealing the contact interface and conformational changes brought about by the interaction. Furthermore, we have calculated an atomic model of the portal protein VP2 and revealed the structural changes in VP1 that lead to pore formation. While VP2 was known to be critical for the production of infectious virus, its function has been hitherto undetermined. Our finding that VP2 assembles a portal that is likely responsible for endosome escape represents a major step forward in our understanding of both the Caliciviridae and icosahedral RNA containing viruses in general.

microbiology↗

bioRxiv2017

The translational landscape of Zika virus during infection of mammalian and insect cells

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus recently associated with congenital diseases and neurological complications. As for all flaviviruses, the ZIKV RNA genome is expected to encode a single polyprotein with all the enzymatic activities required for viral replication. Here, we report the discovery of multiple non-canonical open reading frames (ORFs) identified by ribosome profiling. In both mammalian and insect cells infected with Asian/American and African ZIKV strains, we observed translation of previously unrecognised upstream ORFs (uORFs) in the 5' region. In the Asian/American ZIKV lineage, ribosomes translated uORF1 and uORF2 that initiated from non-AUG start codons, whereas in the African ZIKV lineage, these two uORFs were fused into a single uORF (African uORF). Using a reverse genetics system, we examined the impact on ZIKV fitness of the expression of single or dual uORFs by analysing a panel of mutant viruses. We found that expression of the African uORF, and more significantly, the Asian/American uORF1, modulated virus growth and tropism in human cortical neurons and 3D organoid tissue, indicating that these novel uORFs contribute to ZIKV neurotropism. Although ZIKV uORFs are expressed in mosquito cells, they did not have a detectable effect on transmission by the mosquito vector in vivo. Our discovery of ZIKV uORFs sheds new light on ZIKV-induced neuropathogenesis and raises the question of their existence in other neurotropic flaviviruses.

microbiology↗