title: Early intranuclear replication of African swine fever virus genome modifies the landscape of the host cell nucleus.
abstract: Although African swine fever virus (ASFV) replicates in viral cytoplasmic factories, the presence of viral DNA within the host cell nucleus has been previously reported to be essential for productive infection. Herein, we described, for the first time, the intranuclear distribution patterns of viral DNA replication events, preceding those that occur in the cytoplasmic compartment. Using BrdU pulse-labelling experiments, newly synthesized ASFV genomes were exclusively detected inside the host cell nucleus at the early phase of infection, both in swine monocyte-derived macrophages (MDMs) and Vero cells. From 8hpi onwards, BrdU labelling was only observed in ASFV cytoplasmic factories. Our results also show that ASFV specifically activates the Ataxia Telangiectasia Mutated Rad-3 related (ATR) pathway in ASFV-infected swine MDMs from the early phase of infection, most probably because ASFV genome is recognized as foreign DNA. Morphological changes of promyelocytic leukaemia nuclear bodies (PML-NBs), nuclear speckles and Cajal bodies were also found in ASFV-infected swine MDMs, strongly suggesting the viral modulation of cellular antiviral responses and cellular transcription, respectively. As described for other viral infections, the nuclear reorganization that takes place during ASFV infection may also provide an environment that favours its intranuclear replication events. Altogether, our results contribute for a better understanding of ASFV replication strategies, starting with an essential intranuclear DNA replication phase which induces host nucleus changes towards a successful viral infection.
authors.affiliation: CIISA, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Simões
authors.affiliation: CIISA, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Martins
authors.affiliation: CIISA, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal. Electronic address: fernandof@fmv.ulisboa.pt.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ferreira
mesh_terms: D000358:African Swine Fever Virus / Q000502:physiology*; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D001973:Bromodeoxyuridine / Q000378:metabolism; D002467:Cell Nucleus / Q000648:ultrastructure* / Q000821:virology*; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000821:virology; D004847:Epithelial Cells / Q000821:virology; D008264:Macrophages / Q000821:virology; D015398:Signal Transduction; D013194:Staining and Labeling; D013552:Swine; D014709:Vero Cells; D014779:Virus Replication
chemical_list: D064007:Ataxia Telangiectasia Mutated Proteins; D001973:Bromodeoxyuridine
keywords: African swine fever virus (ASFV); Ataxia telangiectasia mutated rad-3 related (ATR) pathway; BrdU pulse; DNA damage response (DDR); DNA replication; Subnuclear domains