Role of the host cell nucleus in the replication of African swine fever virus DNA.
An examination by autoradiography of African swine fever virus-infected alveolar macrophages pulse labeled with [3H]thymidine showed that, at early times of viral DNA replication, the grains were localized exclusively in the nucleus in 20% of the cells, while in 45% the label was found in the cytoplasm. In the remaining 35%, newly synthesized DNA was detected in both the nucleus and the cytoplasm. At later times, the percentage of cells with grains in the nucleus decreased considerably. Pulse-chase experiments indicated that the DNA synthesized in the nucleus is then transported to the cytoplasm. The presence of virus-specific DNA sequences in the nucleus was confirmed by in situ hybridization of infected macrophages. Similar hybridization experiments with African swine fever virus-infected VERO cells followed by confocal microscopy also indicated the existence of a nuclear stage in the localization of the viral DNA. These results suggest a mechanism for African swine fever virus DNA replication with an initial stage in the nucleus followed by a cytoplasmic phase. Specific nuclear forms associated with the hybridization signal have been observed in African swine fever virus-infected macrophages and VERO cells. The nuclear forms seen in macrophages are consistent with a mechanism for the egress of the viral DNA from the nucleus that involves initial budding at the nuclear membrane.
García-Beato
R
R
Centro de Biología Molecular, (CSIC-UAM), Facultad de Ciencias, Universidad Autónoma, Madrid, Spain.
Salas
M L
ML
Viñuela
E
E
Salas
J
J
D000358:African Swine Fever Virus / Q000235:genetics*; D000818:Animals; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000235:genetics* / Q000378:metabolism; D066298:In Vitro Techniques; D016676:Macrophages, Alveolar / Q000382:microbiology; D009693:Nucleic Acid Hybridization; D013552:Swine; D014709:Vero Cells; D014779:Virus Replication / Q000187:drug effects
D002087:Butyrates; D004279:DNA, Viral; D020148:Butyric Acid