Nuclear speckles may be the unseen architects of viral infection spread

Recent research reveals that nuclear speckles play a key role in modifying viral messenger RNAs and in their transport out of the nucleus; therefore, nuclear speckles are an important subject of study in understanding viral infections.

Herpes simplex virus type 1 (HSV-1) infection dramatically remodels the host cell's nuclear structures. Infection leads to the formation of viral replication compartments and to chromatin marginalization to the nuclear periphery. In addition, a joint research by the Universities of Jyväskylä and Bar-Ilan revealed that viral infection also alters the structure of nuclear speckles, which are essential for messenger RNA processing.

- Nuclear speckles are dynamic, membraneless nuclear bodies that primarily function as sites for the storage, assembly, and modification of factors involved in gene expression. Both cellular and viral messenger RNAs are processed in nuclear speckles. The disassembly of nuclear speckles severely limits the export of viral messenger RNAs from the nucleus, explains Research Director Maija Vihinen-Ranta from the University of Jyväskylä.

Altogether, the research indicates that nuclear speckles function as intermediate hubs for the modification of viral messenger RNAs, thereby highlighting their essential role in viral messenger RNA processing and nuclear export pathways. Without them, virus cannot function normally, and infection cannot progress.

- A better understanding of how viruses interact with host cells and exploit their cellular machinery can help us develop new ways to treat and prevent viral diseases, says Vihinen-Ranta.

The study was published in the prestigious Proceedings of the National Academy of Sciences (PNAS) journal and was conducted in cooperation Professor Shav-Tal's research group Bar-Ilan University (Israel).

The research was financed by the National Institute of Health (USA), the Jane and Aatos Erkko Foundation, the Academy of Finland, the Erasmus programme of the European Union, and the European Union's Horizon 2020.