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Highly pathogenic coronaviruses have caused significant outbreaks in humans and animals, posing a serious threat to public health. The rapid global spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in millions of infections and deaths. However, the mechanisms through which coronaviruses evade a host's antiviral immune system are not well understood. Liquid–liquid phase separation (LLPS) is a recently discovered mechanism that can selectively isolate cellular components to regulate biological processes, including host antiviral innate immune signal transduction pathways. This review focuses on the mechanism of coronavirus-induced LLPS and strategies for utilizing LLPS to evade the host antiviral innate immune response, along with potential antiviral therapeutic drugs and methods. It aims to provide a more comprehensive understanding and novel insights for researchers studying LLPS induced by pandemic viruses. [ABSTRACT FROM AUTHOR]

Porcine deltacoronavirus (PDCoV) is a newly detected porcine coronavirus causing serious vomiting and diarrhea in piglets, especially newborn piglets. There has been an outbreak of PDCoV in worldwide since 2014, causing significant economic losses in the pig industry. The interferon (IFN)-mediated antiviral response is an important component of virus-host interactions and plays an essential role in inhibiting virus infection. However, the mechanism of PDCoV escaping the porcine immune surveillance is unclear. In the present study, we demonstrated that the PDCoV nucleocapsid (N) protein antagonizes porcine IFN-β production after vesicular stomatitis virus (VSV) infection or poly(I:C) stimulation. PDCoV N protein also suppressed the activation of porcine IFN-β promoter when it was stimulated by porcine RLR signaling molecules. PDCoV N protein targeted porcine retinoic acid-inducible gene I (pRIG-I) and porcine TNF receptor associated factor 3 (pTRAF3) by directly interacting with them. The N-terminal region (1–246 aa) of PDCoV N protein was important for interacting with pRIG-I and interfere its function. We confirmed that PDCoV N antagonizes IFN-β production by associating with pRIG-I to impede it from binding double-stranded RNA. Furthermore, porcine Riplet (pRiplet) was an important activator for pRIG-I by mediating the K63-linked polyubiquitination. However, PDCoV N protein restrained the pRiplet binding pRIG-I to inhibit pRIG-I K63-linked polyubiquitination. Taken together, our results revealed a novel mechanism by which PDCoV N protein interferes with the early activation of pRIG-I in the host antiviral response. The novel findings provide a new insight into PDCoV on evading the host innate immune response and may provide new therapeutic targets and more efficacious vaccines strategies for PDCoV infections.

With the development of viral metagenomics and next-generation sequencing technology, more and more novel parvoviruses have been identified in recent years, including even entirely new lineages. The Parvoviridae family includes a different group of viruses that can infect a wide variety of animals. In this study, systematic analysis was performed to identify the "dark matter" (datasets that cannot be easily attributed to known viruses) of parvoviruses and to explore their genetic diversity from wild birds' cloacal swab samples. We have tentatively defined this parvovirus "dark matter" as a highly divergent lineage in the Parvoviridae family. All parvoviruses showed several characteristics, including 2 major protein-coding genes and similar genome lengths. Moreover, we observed that the novel parvo-like viruses share similar genome organizations to most viruses in Parvoviridae but could not clustered with the established subfamilies in phylogenetic analysis. We also found some new members associated with the Bidnaviridae family, which may be derived from parvovirus. This suggests that systematic analysis of domestic and wild animal samples is necessary to explore the genetic diversity of parvoviruses and to mine for more of this potential dark matter. [ABSTRACT FROM AUTHOR]

Introduction: The bar-headed goose is a typical high-altitude bird that primarily inhabits alpine lakes and wetlands in Central Asia, with a remarkable ability to adapt to high elevations. Previous studies have shown that they can be infected with parasites such as Cryptosporidium spp. At present, there were few reports on its infection with the virus., Methods: In this study, we utilized viral metagenomics to conduct a detailed analysis of the viral components in the fecal samples of bar-headed geese ( Anser indicus ) from the Tibet region of China., Results: Multiple novel viruses were identified including four novel astroviruses, four novel caliciviruses, ten novel circoviruses, and nineteen novel parvoviruses. Among them, four astroviruses shared the highest amino acid sequence identities of 63.45-99.47% with different avastrovirus strains. Four caliciviruses and ten circoviruses were identified as unclassified caliciviruses and unclassified circoviruses, separately. Nineteen parvoviruses clustering into four groups maybe four different novel species of the genus Chaphamaparvovirus ., Conclusion: These newly discovered viruses have potential implications for the health of avian species, particularly bar-headed geese. This study not only helps us understand the health status of bar-headed geese, but also offers crucial genomic information for future disease prevention and treatment strategies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Sun, Wang, Ji, Pei, Sun, Ji, Shen, Wang, Liu, Yang and Zhang.)

Introduction: The bar-headed goose ( Anser indicus ), one of the most well-known high-altitude birds, is renowned for its adaptation to high-altitude environments. Previous studies have shown that they can be infected with highly pathogenic avian influenza; however, there is currently limited research on other viruses in bar-headed geese., Methods: In this study, 10 fecal samples of healthy bar-headed geese were collected, and viral metagenomics method was conducted to identify novel picornaviruses., Results: Seven novel picornaviruses were identified in the fecal samples of bar-headed geese. Most of these picornaviruses were genetically different from other currently known viruses in the NCBI dataset. Among them, PICV4 was determined to be a new species belonging to the Anativirus genus, PICV5 and PICV13 were classified as novel species belonging to the Hepatovirus genus, and the remaining four picornaviruses (PICV1, PICV19, PICV21, and PICV22) were identified as part of the Megrivirus A species of the Megrivirus genus. Recombinant analysis indicates that PICV21 was a potential recombinant, and the major and minor parents were PICV1 and PICV22, respectively., Conclusion: The findings of this study increase our understanding of the diversity of picornaviruses in bar-headed geese and provide practical viral genome information for the prevention and treatment of potential viral diseases affecting this species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Sun, Wang, Ji, Zhao, Shen, Wang, Liu, Ji, Yang and Zhang.)