The nuclear lamina is a dense network of intermediate filaments beneath the inner nuclear membrane. Composed of A-type lamins (lamin A/C) and B-type lamins (lamins B1 and B2), the nuclear lamina provides a scaffold for the nuclear envelope and chromatin, thereby maintaining the structural integrity of the nucleus. A-type lamins are also found inside the nucleus where they interact with chromatin and participate in gene regulation. Viruses replicating in the cell nucleus have to overcome the nuclear envelope during the initial phase of infection and during the nuclear egress of viral progeny. Here, we focused on the role of lamins in the replication cycle of a dsDNA virus, mouse polyomavirus. We detected accumulation of the major capsid protein VP1 at the nuclear periphery, defects in nuclear lamina staining and different lamin A/C phosphorylation patterns in the late phase of mouse polyomavirus infection, but the nuclear envelope remained intact. An absence of lamin A/C did not affect the formation of replication complexes but did slow virus propagation. Based on our findings, we propose that the nuclear lamina is a scaffold for replication complex formation and that lamin A/C has a crucial role in the early phases of infection with mouse polyomavirus.

• Keywords
• VP1, lamin A/C, lamin B, mouse polyomavirus, viral replication centres,
• MeSH
• Cell Nucleus metabolism   virology   MeSH
• Phosphorylation MeSH
• Tumor Virus Infections virology   pathology   metabolism   genetics   MeSH
• Nuclear Lamina * metabolism   virology   MeSH
• Nuclear Envelope metabolism   virology   MeSH
• Lamin Type A * metabolism   genetics   MeSH
• Lamin Type B metabolism   genetics   MeSH
• Mice MeSH
• Polyomavirus Infections * virology   metabolism   genetics   pathology   MeSH
• Polyomavirus * genetics   pathogenicity   physiology   MeSH
• Virus Replication * MeSH
• Capsid Proteins metabolism   genetics   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Lamin Type A * MeSH
• Lamin Type B MeSH
• Capsid Proteins MeSH
• VP1 protein, polyomavirus MeSH Browser

Promyelocytic leukemia nuclear bodies (PM NBs), often referred to as membraneless organelles, are dynamic macromolecular protein complexes composed of a PML protein core and other transient or permanent components. PML NBs have been shown to play a role in a wide variety of cellular processes. This review describes in detail the diverse and complex interactions between small and medium size DNA viruses and PML NBs that have been described to date. The PML NB components that interact with small and medium size DNA viruses include PML protein isoforms, ATRX/Daxx, Sp100, Sp110, HP1, and p53, among others. Interaction between viruses and components of these NBs can result in different outcomes, such as influencing viral genome expression and/or replication or impacting IFN-mediated or apoptotic cell responses to viral infection. We discuss how PML NB components abrogate the ability of adenoviruses or Hepatitis B virus to transcribe and/or replicate their genomes and how papillomaviruses use PML NBs and their components to promote their propagation. Interactions between polyomaviruses and PML NBs that are poorly understood but nevertheless suggest that the NBs can serve as scaffolds for viral replication or assembly are also presented. Furthermore, complex interactions between the HBx protein of hepadnaviruses and several PML NBs-associated proteins are also described. Finally, current but scarce information regarding the interactions of VP3/apoptin of the avian anellovirus with PML NBs is provided. Despite the considerable number of studies that have investigated the functions of the PML NBs in the context of viral infection, gaps in our understanding of the fine interactions between viruses and the very dynamic PML NBs remain. The complexity of the bodies is undoubtedly a great challenge that needs to be further addressed.

• Keywords
• DNA viruses, Daxx, PML, PML nuclear bodies, SUMOylation, Sp100, Sp110,
• MeSH
• Adenoviridae MeSH
• DNA Viruses * genetics   MeSH
• Nuclear Proteins * metabolism   MeSH
• Promyelocytic Leukemia Nuclear Bodies MeSH
• Promyelocytic Leukemia Protein metabolism   MeSH
• Transcription Factors metabolism   MeSH
• Viruses MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Nuclear Proteins * MeSH
• Promyelocytic Leukemia Protein MeSH
• Transcription Factors MeSH

DNA virus infections are often lifelong and can cause serious diseases in their hosts. Their recognition by the sensors of the innate immune system represents the front line of host defence. Understanding the molecular mechanisms of innate immunity responses is an important prerequisite for the design of effective antivirotics. This review focuses on the present state of knowledge surrounding the mechanisms of viral DNA genome sensing and the main induced pathways of innate immunity responses. The studies that have been performed to date indicate that herpesviruses, adenoviruses, and polyomaviruses are sensed by various DNA sensors. In non-immune cells, STING pathways have been shown to be activated by cGAS, IFI16, DDX41, or DNA-PK. The activation of TLR9 has mainly been described in pDCs and in other immune cells. Importantly, studies on herpesviruses have unveiled novel participants (BRCA1, H2B, or DNA-PK) in the IFI16 sensing pathway. Polyomavirus studies have revealed that, in addition to viral DNA, micronuclei are released into the cytosol due to genotoxic stress. Papillomaviruses, HBV, and HIV have been shown to evade DNA sensing by sophisticated intracellular trafficking, unique cell tropism, and viral or cellular protein actions that prevent or block DNA sensing. Further research is required to fully understand the interplay between viruses and DNA sensors.

• Keywords
• DNA sensing, DNA viruses, IFI16, IFN, STING, TLR9, cGAS, inflammasome, innate immunity, p204/Ifi-204,
• MeSH
• DNA, Viral metabolism   MeSH
• Herpesviridae * genetics   metabolism   MeSH
• DNA Virus Infections * MeSH
• Humans MeSH
• Polyomavirus * genetics   MeSH
• Immunity, Innate MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• DNA, Viral MeSH

The nuclear lamina is the main component of the nuclear cytoskeleton that maintains the integrity of the nucleus. However, it represents a natural barrier for viruses replicating in the cell nucleus. The lamina blocks viruses from being trafficked to the nucleus for replication, but it also impedes the nuclear egress of the progeny of viral particles. Thus, viruses have evolved mechanisms to overcome this obstacle. Large viruses induce the assembly of multiprotein complexes that are anchored to the inner nuclear membrane. Important components of these complexes are the viral and cellular kinases phosphorylating the lamina and promoting its disaggregation, therefore allowing virus egress. Small viruses also use cellular kinases to induce lamina phosphorylation and the subsequent disruption in order to facilitate the import of viral particles during the early stages of infection or during their nuclear egress. Another component of the nuclear cytoskeleton, nuclear actin, is exploited by viruses for the intranuclear movement of their particles from the replication sites to the nuclear periphery. This study focuses on exploitation of the nuclear cytoskeleton by viruses, although this is just the beginning for many viruses, and promises to reveal the mechanisms and dynamic of physiological and pathological processes in the nucleus.

• Keywords
• adenovirus, baculovirus, circovirus, herpesvirus, lamin, nuclear actin, nuclear cytoskeleton, papillomavirus, parvovirus, polyomavirus,
• MeSH
• Actins metabolism   MeSH
• Cell Nucleus metabolism   MeSH
• Cytoskeleton genetics   metabolism   MeSH
• Species Specificity MeSH
• Host-Pathogen Interactions * MeSH
• Nuclear Lamina metabolism   MeSH
• Nuclear Envelope metabolism   MeSH
• Lamins metabolism   MeSH
• Humans MeSH
• Disease Susceptibility * MeSH
• Gene Expression Regulation, Viral MeSH
• Virus Replication MeSH
• Virus Diseases etiology   metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Actins MeSH
• Lamins MeSH