Biology subjects

Cosic, A.

Publications and source records attributed to Cosic, A..

2 recordsLinked to original sources

bioRxiv2025

Comparative analysis of NSP5/VP2-induced viroplasm-like structures in rotavirus species A to J

Rotavirus (RV) is classified into nine species, A-D and F-J, with RV species A (RVA) being the most extensively studied. While RVA infects infants and young animals, non-RVA species infect adult humans, various mammals, and birds. However, the lack of appropriate research tools has limited our understanding of non-RVA life cycles. RVA replication and assembly occur in cytosolic inclusions termed viroplasms. We recently identified viroplasm-like structures (VLS) composed of NSP5 and NSP2, designated as VLS(NSP2)i, in non-RVA. In this context, globular VLS(NSP2)i formed in RVA, RVB, RVD, RVF, RVG, and RVI, but not in RVC, RVH, and RVJ. Additionally, in RVA, VLS can also be formed through co-expression of NSP5 with VP2, referred to as VLS(VP2)i. Here, we report VLS(VP2)i formation in all non-RVA species except RVB, with notable VLS formation in RVH and RVJ. Moreover, NSP2 RVH or RVJ are recruited into VLS(VP2)i. The NSP5 C-terminal region in non-RVA is required for association with VP2 and forming VLS(VP2)i. Mutation of conserved VP2-L141 in RVA to alanine disrupts viroplasm formation, impairing RV replication. Equivalent residues within the same predicted VP2 region disrupt VLS formation across non-RVA. We also observed interspecies VLS formation, particularly between closely related RVA and RVC, RVH and RVJ, and RVD and RVF. Interestingly, substituting the N-terminal region of VP2 RVB with that of the closely related VP2 RVG restores its ability to form VLS with NSP5 RVB. Elucidating the formation of viroplasms is essential for developing strategies to halt infection across RV species A to J. ImportanceRotaviruses (RV) are a group of viruses classified into species A through J, with species A being the best understood. Other RV species infecting animals and humans are less studied due to limited research tools. In RVA, the virus replicates in specialized compartments called viroplasms formed in the cytoplasm by viral proteins, including NSP5, NSP2, and VP2. In this study, we explored how similar structures, termed viroplasm-like structures (VLS), are formed by proteins of other RV species. We found that in most species, NSP5 and VP2 form VLSs. One exception was RVB, where VLS formation was observed only when the VP2 protein was mutated to resemble that of a related species. We also identified key regions in the VP2 protein that are essential for forming these structures. Understanding how viroplasms form across different RV species may help develop new strategies to block infection in humans and animals.

microbiology↗

bioRxiv2024

Characterization of Viroplasm-Like Structures by Co-Expression of NSP5 and NSP2 Across Rotavirus Species A to J

Rotaviruses (RV) are classified into nine species, A-C and D-J, with species A being the most studied. In rotavirus of species A (RVA), replication occurs in viroplasms, which are cytosolic globular inclusions primarily composed of the proteins NSP5, NSP2, and VP2. The co-expression of NSP5 with either NSP2 or VP2 leads to the formation of viroplasm-like structures (VLS). Although morphologically identical to viroplasms, VLSs cannot replicate, but they serve as excellent simplified tools for studying complex viroplasms. There is a knowledge gap regarding viroplasms of non-RVA species due to a lack of research tools, such as specific antibodies and tissue culture systems. In this study, we explored the ability of NSP5 and NSP2 from non-RVA species to form VLSs. The co-expression of these two proteins led to globular VLSs in RV species A, B, D, F, G, and I, while RVC formed filamentous VLSs. The co-expression of NSP5 and NSP2 of RV species H and J did not result in VLS formation. Interestingly, NSP5 of all RV species self-oligomerizes, with the ordered C-terminal region, termed the tail, being necessary for self-oligomerization of RV species A-C and G-J. Except for NSP5 from species J, all NSP5 bound with their respective NSP2. We also found that interspecies VLS are formed between closely related RV species B with G and D with F. Additionally, VLS from RVH and RVJ formed when the tail of NSP5 RVH and RVJ was replaced by the tail of NSP5 from RVA and co-expressed with their respective NSP2. ImportanceRotaviruses (RV) are classified into nine species, A-D and F-J, infecting mammals and birds. Due to the lack of research tools, all cumulative knowledge on RV replication is based on RV species A (RVA). The RV replication compartments are globular cytosolic structures named viroplasms, which have only been identified in RV species A. In this study, we examined the formation of viroplasm-like structures (VLS) by the expression of NSP5 with NSP2 across RV species A to J. Globular VLSs formed for RV species A, B, D, F, G, and I, while RV species C formed filamentous structures. The RV species H and J did not form VLS with NSP5 and NSP2. Similar to RVA, NSP5 self-oligomerizes in all RV species, which is a requirement for VLS formation. This study provides basic knowledge of the non-RVA replication mechanisms, which could help develop strategies to halt virus infection across RV species.

microbiology↗