Biology subjects

Mascheroni, L.

Publications and source records attributed to Mascheroni, L..

3 recordsLinked to original sources

bioRxiv2021

The SARS-CoV-2 nucleocapsid protein associates with the replication organelles before viral assembly at the Golgi/ERGIC and lysosome-mediated egress

Despite being the target of extensive research efforts due to the COVID-19 pandemic, relatively little is known about the dynamics of SARS-CoV-2 replication within cells. We investigate and characterise the tightly orchestrated sequence of events during different stages of the infection cycle by visualising the spatiotemporal dynamics of the four structural proteins of SARS-CoV-2 at high resolution. The nucleoprotein is expressed first and accumulates around folded ER membranes in convoluted layers that connect to viral RNA replication foci. We find that of the three transmembrane proteins, the membrane protein appears at the Golgi apparatus/ERGIC before the spike and envelope proteins. Relocation of the lysosome marker LAMP1 towards the assembly compartment and its detection in transport vesicles of viral proteins confirm an important role of lysosomes in SARS-CoV-2 egress. These data provide new insights into the spatiotemporal regulation of SARS-CoV-2 assembly, and refine current understanding of SARS-CoV-2 replication.

microbiology↗

bioRxiv2020

Combining light sheet microscopy and expansion microscopy for fast 3D imaging of virus-infected cells with super-resolution

Expansion microscopy is a sample preparation technique that enables the optical imaging of biological specimens at super-resolution owing to their physical magnification, which is achieved through water-absorbing polymers. The technique uses readily available chemicals and does not require sophisticated equipment, thus offering super-resolution to laboratories that are not microscopy-specialised. Here we present a protocol combining sample expansion with light sheet microscopy to generate high-contrast, high-resolution 3D reconstructions of whole virus-infected cells. The results are superior to those achievable with comparable imaging modalities and reveal details of the infection cycle that are not discernible before expansion. An image resolution of approximately 95 nm could be achieved in samples labelled in 3 colours. We clearly resolve the concentration of viral nucleoprotein on the surface of vesicular structures within the cell and their positioning relative to cellular organelles. We provide detailed guidance and a video protocol for the optimal application of the method and demonstrate its potential to study virus-host cell interactions.

microbiology↗

bioRxiv2019

Spatiotemporal analysis of host cell modification during herpes simplex virus 1 replication

Herpesviruses are large and complex viruses, and have a long evolutionary history with their host species. One poorly understood, but important, area in virus-host interaction is the extensive remodelling of intracellular organelles and morphology that occurs during active viral replication. We have constructed a recombinant reporter virus that allowed us to classify four distinct stages in the infection cycle of herpes simplex virus 1. Single-cell analysis of the impact of the viral load on replication dynamics demonstrates the utility of this times-tamping method for tracking the infection cycle. High-resolution microscopy analysis of cellular structures in live and fixed cells in concert with our dual-fluorescent reporter virus have enabled us to generate a detailed overview over the spatial and temporal organisation of the cytoskeleton and organelles during viral replication. This provides the first systems-level analysis of the morphological changes involved in viral replication.

microbiology↗