Viruses are strictly intracellular parasites requiring host cellular functions to complete their reproduction cycle involving virus infection of host cell, viral genome replication, viral protein translation, and virion release. Ribosomes are protein synthesis factories in cells, and viruses need to manipulate ribosomes to complete their protein synthesis. Viruses use translation initiation factors through their own RNA structures or cap structures, thereby inducing ribosomes to synthesize viral proteins. Viruses also affect ribosome production and the assembly of mature ribosomes, and regulate the recognition of mRNA by ribosomes, thereby promoting viral protein synthesis and inhibiting the synthesis of host antiviral immune proteins. Here, we review the remarkable mechanisms used by RNA viruses to regulate ribosomes, in particular, the mechanisms by which RNA viruses induce the formation of specific heterogeneous ribosomes required for viral protein translation. This review provides valuable insights into the control of viral infection and diseases from the perspective of viral protein synthesis.

Viral infections in swine, such as African swine fever (ASF), porcine reproductive and respiratory syndrome (PRRS), and foot-and-mouth disease (FMD), have a significant impact on the swine industry. Despite the significant progress in the recent efforts to develop effective vaccines against viral diseases in swine, the search for new protective vaccination strategy remains a challenge. The antigenic epitope, acting as a fundamental unit, can initiate either a cellular or humoral immune response. Consequently, the combination of multi-epitopes expressing different stages of viral life cycle has become an optimal strategy for acquiring a potent, safe, and effective vaccine for preventing and treating viral diseases in swine. Recent progresses in immunoinformatic tools, coupled with an understanding of host immune responses and computational biology, have paved the way for innovative vaccine design disciplines that focus on computer-assisted, in-silico epitope prediction for the prevention of viral diseases in swine. The concept of multi-epitope vaccines driven by immunoinformatic methods has gained prominence in multiple studies, particularly in the development of vaccines targeting conserved epitopes in variable or rapidly mutating pathogens such as African swine fever virus (ASFV) and porcine reproductive and respiratory syndrome virus (PRRSV). In this review, we provide an overview of the in-silico design of the multi-epitope vaccines against viral diseases in swine, including the antigenicity, structural quality analysis, immune simulations, and molecular dynamics (MD) simulations. Furthermore, we also enumerate several multi-epitope vaccine applications that have shown promise to be against viral diseases in swine.

Commonly used tests based on wild-type viruses, such as immunostaining, cannot meet the demands for rapid detection of viral replication, high-throughput screening for antivirals, as well as for tracking viral proteins or virus transport in real time. Notably, the development of replicating-competent reporter-expressing viruses (RCREVs) has provided an excellent option to detect directly viral replication without the use of secondary labeling, which represents a significant advance in virology. This article reviews the applications of RCREVs in diagnostic and molecular virology, including rapid neutralization tests, high-throughput screening systems, identification of viral receptors and virus-host interactions, dynamics of viral infections in vitro and in vivo, vaccination approaches and others. However, there remain various challenges associated with RCREVs, including pathogenicity alterations due to the insertion of a reporter gene, instability or loss of the reporter gene expression, or attenuation of reporter signals in vivo. Despite all these limitations, RCREVs have become powerful tools for both basic and applied virology with the development of new technologies for generating RCREVs, the inventions of novel reporters and the better understanding of regulation of viral replication.

The p6 domain of the Gag precursors (Gag p6) in human immunodeficiency virus type 1 (HIV-1) plays multifunctional roles in the viral life cycle. It utilizes the endosomal sorting complex required for transport (ESCRT) system to facilitate viral budding and release from the plasma membrane through the interactions with the ESCRT-I component tumor susceptibility gene 101 (TSG101) and with the ALG-2 interacting protein X (ALIX). Moreover, Gag p6 contributes to viral replication by a range of posttranslational modifications such as SUMOylation, ubiquitination and phosphorylation. Additionally, Gag p6 also mediates the incorporation of the accessory protein Vpr into virions, thereby promoting Vpr-induced viral replication. However, less attention is focused on Gag p6 as therapeutic intervention. This review focuses on the structures and diverse functions of Gag p6 in viral replication, host cells, and pathogenesis. Additionally, several challenges were also discussed in studying the structure of Gag p6 and its interactions with partners. Consequently, it concludes that the Gag p6 represents an attractive target for the development of antiretroviral drugs, and efforts to develop p6-targeted antiretrovirals are expected to undergo significant growth in the forthcoming years.