Alexander Borodavka

Thursday, 26 April 2018 | 12:00 noon

Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, UK

These can go up to eleven’: shedding light on the molecular mechanisms of genome segment counting in rotaviruses

(Host: O. Burrone)

Genome segmentation offers certain evolutionary benefits to a number of pathogenic RNA viruses, including rotaviruses and influenza viruses. However, as the number of RNA segments per virion increases, the task of a non-random selection of afull set of distinct genomic RNAs poses a formidable challenge to maintaining the integrity of segmented genomes.Recently we have identified sequence-specific inter-segment interactions between rotavirus (+)ssRNA genome segment precursors. We have shown that binding of the rotavirus-encoded non-structural protein NSP2 to viral ssRNAs resultsin the remodeling of RNA, which is conducive to formation ofinter-segment contacts.

These protein-RNA interactions result in the stabilisation of extended intermolecular RNA-RNAcontacts, potentially underpinning transient inter-segmentinteractions prior to genome encapsidation and replication.Using this approach we have identified a number of RNA-RNAinteraction sites in the rotavirus genome, which are likely to be involved in genome segment assortment process.

Having established the role of NSP2 in promoting inter-segment RNA-RNA contacts, we are developing super-resolution imaging tools for direct visualization of the RNA assortment complexes in rotavirus-infected cells. To unravel the mechanisms by which NSP2 controls the formation ofinter-molecular RNA helices we have applied RNA structure probing methods that allowed us to monitor conformational rearrangements, which are prerequisite for formation of theRNA assortment complex. Our findings open up uniqueavenues for understanding the challenges for further improvement of the recently developed fully plasmid-basedreverse genetics systems for rotaviruses.