Biology subjects

Mahboubi, A.

Publications and source records attributed to Mahboubi, A..

2 recordsLinked to original sources

bioRxiv2022

Cauliflower mosaic virus protein P6 forms a microenvironment for RNA granule proteins and interferes with stress granule responses

Biomolecular condensation is a multipurpose cellular process that viruses use ubiquitously in their multiplication. CaMV replication complexes are condensates that differ from most viruses in being non-membranous assemblies and consist of RNA and protein, mainly viral protein P6. Despite description of these viral factories already half a century ago with many observations that followed since, functional details of the condensation process, their properties and relevance has remained enigmatic. Our main findings include a large dynamic mobility range of host proteins within viral factories, while the viral matrix protein P6 is immobile in accordance with representing the central node of these condensates. As novel components of VFs we identify stress granule (SG) nucleating factors G3BP7 and the UBP1 family. Similarly, as SG components localize in VFs during infection, ectopic P6 localizes to SGs and reduces their assembly after stress. Intriguingly, it appears that soluble rather than condensed P6 suppresses SGs and mediates also other essential P6 functions, suggesting that the increased condensation over the infection time-course may accompany a progressive shift in selected P6 functions. Together, this study highlights VFs as dynamic condensates and P6 as a complex modulator of SG responses.

plant biology↗

bioRxiv2021

Cauliflower Mosaic Virus Utilizes Processing Bodies to Escape Translational Repression in Arabidopsis

Viral infections impose extraordinary RNA stress on a cell, triggering cellular RNA surveillance pathways like RNA decapping, nonsense-mediated decay and RNA silencing. Viruses need to maneuver between these pathways to establish infection and succeed in producing high amounts of viral proteins. Processing bodies (PBs) are integral to RNA triage in eukaryotic cells with several distinct RNA quality control pathways converging for selective RNA regulation. In this study, we investigate the role of Arabidopsis thaliana PBs during Cauliflower Mosaic Virus (CaMV) infection. We find that several PB components are co-opted into viral replication factories and support virus multiplication. This pro-viral role was not associated with RNA decay pathways but instead, we could establish PB components as essential helpers in viral RNA translation. While CaMV is normally resilient to RNA silencing, PB dysfunctions expose the virus to this pathway, similar to previous observations on transgenes. Transgenes, however, undergo RNA Quality Control dependent RNA degradation, whereas CaMV RNA remains stable but becomes translationally repressed through decreased ribosome association, revealing a unique dependence between PBs, RNA silencing and translational repression. Together, our study shows that PB components are co-opted by the virus to maintain efficient translation, a mechanism not associated with canonical PB functions.

plant biology↗