Capsid Proteins ; metabolism ; Endocytosis ; physiology ; Virus Internalization ; Viruses ; metabolism

Animals ; Humans ; Mucous Membrane ; immunology ; metabolism ; virology ; Viruses ; immunology

The innate immune system acts as the first line of defense against pathogens, which is also essential for initiation of adaptive immunity. Innate immune responses are initiated by pattern-recognition receptors (PRRs), which recognize conserved molecular structures of pathogens called pathogen-associated molecular patterns (PAMPs). The infection of virus triggers a series of signaling events leading to transcriptional induction of type I interferons (IFNs) and proinflammatory cytokines. In recent years, the mechanisms of viral RNA recognition and RNA virus-triggered signaling pathways have been well studied. However, it remains unclear on how DNA virus infection is sensed by host cells and triggers the host antiviral defense. Although ten potential viral DNA sensors have been reported, none of them is validated as a generally used sensor for distinct DNA viruses in divergent cell types and animals. Here, we provide a summary and perspective on recent advances in innate immune responses to DNA viruses.
Animals ; DNA Viruses ; immunology ; Humans ; Immunity, Innate ; Proteins ; metabolism

Endosomal sorting complex required for transport (ESCRT) system drives various cellular processes, including endosome sorting, organelle biogenesis, vesicle transport, maintenance of plasma membrane integrity, membrane fission during cytokinesis, nuclear membrane reformation after mitosis, closure of autophagic vacuoles, and enveloped virus budding. Increasing evidence suggests that the ESCRT system can be hijacked by different family viruses for their proliferation. At different stages of the virus life cycle, viruses can interfere with or exploit ESCRT-mediated physiological processes in various ways to maximize their chance of infecting the host. In addition, many retroviral and RNA viral proteins possess "late domain" motifs, which can recruit host ESCRT subunit proteins to assist in virus endocytosis, transport, replicate, budding and efflux. Therefore, the "late domain" motifs of viruses and ESCRT subunit proteins could serve as promising drug targets in antiviral therapy. This review focuses on the composition and functions of the ESCRT system, the effects of ESCRT subunits and virus "late domain" motifs on viral replication, and the antiviral effects mediated by the ESCRT system, aiming to provide a reference for the development and utilization of antiviral drugs.
Endosomal Sorting Complexes Required for Transport/metabolism* ; Viruses/metabolism* ; Protein Transport ; Virus Replication ; Endosomes/metabolism* ; Virus Release

Microbe is extremely abundant in nature, and its size has a very wide coverage from nano- to micro-scale making it suitable to be processed at multi-scale level as natural "building blocks" and "chassis cells". Biofabrication based on microbes is an artificial manipulation on microbes to assemble functional materials and devices by using the specific structures and various biological functions of microbes. In the meantime, the novel strategies of biofarication enables us to study the behavioral details of microbes, which will provide new platforms for uncovering the unsolved basic scientific problems of microbes. In this paper, we reviewed the frontier and progress in biofabrication from nano- and micro-scale in microbes that were manipulated as structured "building blocks" or functional "micro/nano robots".
Bacteria ; metabolism ; Biomimetics ; methods ; Biotechnology ; Microfluidic Analytical Techniques ; methods ; Nanotechnology ; Viruses ; metabolism

Ubiquitin is highly conserved 76 amino acid protein found in all eukaryotic organisms and ubiquitin-proteasome pathway (UPP) plays a very important role in regulated non-lysosomal ATP dependent protein degradation. This pathway participates in or regulates numerous cellular processes, such as selective protein degradation, cell cycle progression, apoptosis, signal transduction, transcriptional regulation, receptor control by endocytosis, immune response and the processing of antigens. Nevertheless, roles of UPP in virus infection are only beginning to be clarified. Ubiquitin homology has also been found in insect viruses. All viral ubiquitin genes encode an N-terminal ubiquitin sequence and 3-256 amino acids C-terminal peptides. Most of the residues known to be essential for ubiquitin function have been conserved in the viral variant. In Autographa californica nucleopolyhedrovirus (AcMNPV), viral ubiquitin is attached to the inner surface of budded viron membrane by a covalently linked phospholipid and is not essential for viral replication. Currently, insect viruses are the only viruses known to encode ubiquitin. However, ubiquitin also plays a role in the life cycle of other viruses. Host ubiquitin molecules have been found in some plant viruses and other animal viruses. Additionally, Africa swine fever virus (ASFV) encodes a ubiquitin-conjugating enzyme (E2) and a putative causal link between human immunodeficiency virus type 1 (HIV-1) and ubiquitin was established by showing that depletion of the intracellular pool of free ubiquitin inhibits the virus budding. Further analyses indicated that many retroviruses proteins which are required for efficient pinching off the virus bud contain a late domain. The core element of the late domain is a proline-rich motif (PPXY) which mediates the late domain to be ubiquitinated by cellular proteins. Recently, it has been shown that many retroviruses have developed mechanisms to escape the cellular immune response, to facilitate virus replication and to promote virus assembly and budding via host UPP.
African Swine Fever Virus ; metabolism ; pathogenicity ; Animals ; Humans ; Insect Viruses ; metabolism ; pathogenicity ; Proteasome Endopeptidase Complex ; metabolism ; Retroviridae ; metabolism ; pathogenicity ; Ubiquitin ; metabolism ; Ubiquitin-Protein Ligase Complexes ; metabolism ; Virus Diseases ; virology ; Viruses ; pathogenicity

Gene Expression Regulation, Viral ; Proteomics ; methods ; trends ; Viral Proteins ; analysis ; genetics ; Viruses ; genetics ; growth & development ; metabolism

A safe and effective targeting viral vector is the key factor for successful clinical gene therapy. microRNA, a class of small, single-stranded endogenous RNAs, act as post-transcriptional regulators of gene expression. The discovery of these kind regulatory elements provides a new approach to regulate gene expression more accurately. In this review, we elucidated the principle of microRNA in regulation of targeting viral vector. The applications of microRNA in the fields of elimination contamination from replication competent virus, reduction of transgene-specific immunity, promotion of cancer-targeted gene therapy and development of live attenuated vaccines were also discussed.
Gene Expression Regulation ; Genetic Therapy ; Genetic Vectors ; genetics ; Humans ; MicroRNAs ; genetics ; Viruses ; genetics ; metabolism

RNA silencing is a conserved eukaryotic pathway involved in the suppression of gene expression via sequence-specific interactions that are mediated by 21-23 nt RNA molecules. During infection, RNAi can act as an innate immune system to defend against viruses. As a counter-defensive strategy, silencing suppressors are encoded by viruses to inhibit various stages of the silencing process. These suppressors are diverse in sequence and structure and act via different mechanisms. In this review, we discuss whether RNAi is a defensive strategy in mammalian host cells and whether silencing suppressors can be encoded by mammalian viruses. We also review the modes of action proposed for some silencing suppressors.
Animals ; Gene Expression Regulation, Viral ; Gene Silencing ; Host-Pathogen Interactions ; Humans ; Mammals ; virology ; MicroRNAs ; genetics ; metabolism ; Plant Viruses ; physiology ; Plants ; virology ; RNA, Small Interfering ; genetics ; metabolism ; Repressor Proteins ; genetics ; metabolism ; Viral Proteins ; genetics ; metabolism ; Viruses ; growth & development

Tumor suppressor p53, known as 'the guardian of the genome', has the ability to prevent the emergence of transformed cells by the induction of cell cycle arrest and apoptosis. Otherwise, there were researches about the function of p53, such as NDA repair, regulating metabolism and maternal reproduction in recent years. Furthermore, there was a new function for p53 in antiviral apoptosis mentioned in the research, Integration of interferon-alpha/beta signaling to p53 responses in tumour suppression and antiviral defense. In order to define the antiviral function of p53, many target genes has been defined, such as IRF9, IRF5, ISG15 and TLR3. All of these implied there must be a complex mechanism for role of p53 in antiviral innate immunity, adaptive immunity and inflammation.
Animals ; Cell Physiological Phenomena ; Humans ; Immunity ; Inflammation ; immunology ; metabolism ; virology ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; Viruses ; immunology