Advances in Virus Research最新文献

Herpes simplex viruses (HSV) cause chronic infection in humans that are characterized by periodic episodes of mucosal shedding and ulcerative disease. HSV causes millions of infections world-wide, with lifelong bouts of viral reactivation from latency in neuronal ganglia. Infected individuals experience different levels of disease severity and frequency of reactivation. There are two distantly related HSV species, with HSV-1 infections historically found most often in the oral niche and HSV-2 infections in the genital niche. Over the last two decades, HSV-1 has emerged as the leading cause of first-episode genital herpes in multiple countries. While HSV-1 has the highest level of genetic diversity among human alpha-herpesviruses, it is not yet known how quickly the HSV-1 viral population in a human host adapts over time, or if there are population bottlenecks associated with viral reactivation and/or transmission. It is also unknown how the ecological environments in which HSV infections occur influence their evolutionary trajectory, or that of co-occurring viruses and microbes. In this review, we explore how HSV accrues genetic diversity within each new infection, and yet maintains its ability to successfully infect most of the human population. A holistic examination of the ecological context of natural human infections can expand our awareness of how HSV adapts as it moves within and between human hosts, and reveal the complexity of these lifelong human-virus interactions. These insights may in turn suggest new areas of exploration for other chronic pathogens that successfully evolve and persist among their hosts.

Parainfluenza viruses, members of the enveloped, negative-sense, single stranded RNA Paramyxoviridae family, impact global child health as the cause of significant lower respiratory tract infections. Parainfluenza viruses enter cells by fusing directly at the cell surface membrane. How this fusion occurs via the coordinated efforts of the two molecules that comprise the viral surface fusion complex, and how these efforts may be blocked, are the subjects of this chapter. The receptor binding protein of parainfluenza forms a complex with the fusion protein of the virus, remaining stably associated until a receptor is reached. At that point, the receptor binding protein actively triggers the fusion protein to undergo a series of transitions that ultimately lead to membrane fusion and viral entry. In recent years it has become possible to examine this remarkable process on the surface of viral particles and to begin to understand the steps in the transition of this molecular machine, using a structural biology approach. Understanding the steps in entry leads to several possible strategies to prevent fusion and inhibit infection.

Alphaviruses are positive-strand RNA viruses, typically transmitted by mosquitoes between vertebrate hosts. They encode four essential replication proteins, the non-structural proteins nsP1-4, which possess the enzymatic activities of RNA capping, RNA helicase, site-specific protease, ADP-ribosyl removal and RNA polymerase. Alphaviruses have been key models in the study of membrane-associated RNA replication, which is a conserved feature among the positive-strand RNA viruses of animals and plants. We review new structural and functional information on the nsPs and their interaction with host proteins and membranes, as well as with viral RNA sequences. The dodecameric ring structure of nsP1 is likely to be one of the evolutionary innovations that facilitated the success of the progenitors of current positive-strand RNA viruses.

The evolution of human-virus associations is usually reconstructed from contemporary patterns of genomic diversity. An intriguing, though still rarely implemented, alternative is to search for the genetic material of viruses in archeological and medical archive specimens to document evolution as it happened. In this chapter, we present lessons from ancient DNA research and incorporate insights from virology to explore the potential range of applications and likely limitations of archeovirological approaches. We also highlight the numerous questions archeovirology will hopefully allow us to tackle in the near future, and the main expected roadblocks to these avenues of research.

Cellular compartmentalization of proteins and protein complex formation allow cells to tightly control biological processes. Therefore, understanding the subcellular localization and interactions of a specific protein is crucial to uncover its biological function. The advent of proximity labeling (PL) has reshaped cellular proteomics in infection biology. PL utilizes a genetically modified enzyme that generates a "labeling cloud" by covalently labeling proteins in close proximity to the enzyme. Fusion of a PL enzyme to a specific antibody or a "bait" protein of interest in combination with affinity enrichment mass spectrometry (AE-MS) enables the isolation and identification of the cellular proximity proteome, or proxisome. This powerful methodology has been paramount for the mapping of membrane or membraneless organelles as well as for the understanding of hard-to-purify protein complexes, such as those of transmembrane proteins. Unsurprisingly, more and more infection biology research groups have recognized the potential of PL for the identification of host-pathogen interactions. In this chapter, we introduce the enzymes commonly used for PL labeling as well as recent promising advancements and summarize the major achievements in organelle mapping and nucleic acid PL. Moreover, we comprehensively describe the research on host-pathogen interactions using PL, giving special attention to studies in the field of virology.

The host cell proteome undergoes a variety of dynamic changes during viral infection, elicited by the virus itself or host cell defense mechanisms. Studying these changes on a global scale by integrating functional and physical interactions within protein networks during infection is an important tool to understand pathology. Indeed, proteomics studies dissecting protein signaling cascades and interaction networks upon infection showed how global information can significantly improve understanding of disease mechanisms of diverse viral infections. Here, we summarize and give examples of different experimental designs, proteomics approaches and bioinformatics analyses that allow profiling proteome changes and host-pathogen interactions to gain a molecular systems view of viral infection.

Bluetongue virus (BTV) is an insect-vectored emerging pathogen of wild ruminants and livestock in many parts of the world. The virion particle is a complex structure of consecutive layers of protein surrounding a genome of 10 double-stranded (ds) RNA segments. BTV has been studied extensively as a model system for large, nonenveloped dsRNA viruses. A combination of recombinant proteins and particles together with reverse genetics, high-resolution structural analysis by X-ray crystallography and cryo-electron microscopy techniques have been utilized to provide an order for the assembly of the capsid shell and the protein sequestration required for it. Further, a reconstituted in vitro assembly system and RNA-RNA interaction assay, have defined the individual steps required for the assembly and packaging of the 10-segmented RNA genome. In addition, various microscopic techniques have been utilized to illuminate the stages of virus maturation and its egress via multiple pathways. These findings have not only given an overall understanding of BTV assembly and morphogenesis but also indicated that similar assembly and egress pathways are likely to be used by related viruses and provided an informed starting point for intervention or prevention.