pp65 mutant human cytomegalovirus infected human fibroblasts

Abstract: We have identified a cytomegalovirus virion protein capable of modulating the rapid induction of an interferon-like response in cells that follows virus binding and penetration. Functional genomics revealed a role for the major cytomegalovirus structural protein, pp65 (ppUL83), in counteracting this response. The underlying mechanism involves a differential impact of this structural protein on the regulation of interferon response factor 3 (IRF-3). In contrast, NF-{kappa}B is activated independent of pp65, and neither STAT1 nor STAT3 becomes activated by either virus. pp65 is sufficient to prevent the activation of IRF-3 when introduced alone into cells. pp65 acts by inhibiting nuclear accumulation of IRF-3 and is associated with a reduced IRF-3 phosphorylation state. Thus, this investigation shows that the major structural protein of cytomegalovirus is committed to the modulation of the IRF-3 response, a primary mediator of the type I interferon response. By subverting IRF-3, the virus escapes throwing a central alarm devoted to both immediate antiviral control and regulation of the immune response. Polyadenylated RNA from 107 confluent HFs was purified by using Oligotex (QIAGEN, Valencia, Calif.) from Trizol (Invitrogen)-extracted total RNA. This RNA was prepared, reverse transcribed, labeled with Cy3-dUTP or Cy5-dUTP (Amersham, Little Chalfont, Buckinghamshire, United Kingdom) by random primed synthesis with DNA pol I Klenow (Amersham Life Science, Inc., Cleveland, Ohio), and hybridized to spotted, human cDNA microarrays as previously described. Sequence-verified human cDNA microarrays (HE and HG series, 31,000 spots; HD51 series, 17,000 spots) were produced at Stanford. Images were collected by using a GenePix 4000B microarray scanner, manually flagged to eliminate poor spots and analyzed by GenePix Pro 2.0 (Axon, Union City, Calif.). A replicate experimental design type is where a series of replicates are performed to evaluate reproducibility or as a pilot study to determine the appropriate number of replicates for a subsequent experiments. User Defined