The nucleus is a highly organised yet dynamic environment containing distinct membraneless nuclear bodies. This spatial separation enables a subset of components to be concentrated within biomolecular condensates, allowing efficient and discrete processes to occur which regulate cellular function. One such nuclear body, paraspeckles, are comprised of multiple paraspeckle proteins (PSPs) built around the architectural RNA, NEAT1_2. Paraspeckle function is yet to be fully elucidated but has been implicated in a variety of developmental and disease scenarios. We demonstrate that Kaposi’s sarcoma-associated herpesvirus (KSHV) drives formation of structurally distinct paraspeckles with a dramatically increased size and altered protein composition that are required for productive lytic replication. We highlight these virus-modified paraspeckles form adjacent to virus replication centres, potentially functioning as RNA processing hubs for viral transcripts during infection. Notably, we reveal that PSP sequestration into virus-modified paraspeckles result in increased genome instability during both KSHV and Epstein Barr virus (EBV) infection, implicating their formation in virus-mediated tumourigenesis.

Foot-and-mouth disease virus (FMDV) is responsible for foot-and-mouth disease (FMD), an important disease of farmed animals, which is endemic in many parts of the world and can results in major economic losses. Replication of the virus occurs within membrane-associated compartments in infected cells and requires highly coordinated processing events to produce an array of nonstructural proteins.

Foot-and-mouth disease virus (FMDV) remains an ever-present threat to the economic stability of the livestock industry and global trade. Despite this, questions remain regarding the fundamental biology underpinning the replication of this virus. Here, we examine components of the FMDV replication machinery (focussing on the viral 2C protein) and investigate the conditions under which they interact. Using a novel 2C antibody in co-immunoprecipitation experiments under different conditions followed by MS, we identify membrane-associated proteins (such as the viral proteins 2B and precursors of 3A, which are poorly characterized proteins involved in viral replication) along with endoplasmic reticulum (ER)-associated host proteins. In addition, our analysis shows that a number of nuclear factors interact with 2C in a membrane-independent manner, potentially being co-opted to support RNA replication of the virus. Furthermore, we demonstrate that the membrane-mediated interaction of 2C with several viral proteins (including key members of the replication machinery and viral RNA) is maintained following ultracentrifugation, suggesting that these co-sediment as part of a complex. Our data suggest that the replication complex is ER-derived and highlight several new avenues of investigation for the disruption of the FMDV lifecycle.

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi’s sarcoma (KS) and several lymphoproliferative diseases. As with all herpesviruses, KSHV replicates in a biphasic manner, with the establishment of a latent, persistent infection from which reactivation occurs, resulting in the completion of the temporal lytic replication cycle and production of infectious virions. Herein, we discuss the impact of KSHV lytic replication on the host cell nucleus and nuclear-related pathways. We highlight the dramatic remodelling of the nuclear architecture driven by the formation of viral replication and transcription centres (vRTCs), and the implications for sub-nuclear organelles, and how pathways involved in DNA damage, ribosomal biogenesis and epitranscriptomic regulation are disrupted or modified during KSHV replication. These changes foster an environment favourable for KSHV replication and may provide novel targets and strategies for therapeutic intervention.