We found that MHV-68 infection induced pronounced invaginations of the INM (). We wished to elucidate the mechanism underlying the cell cycle delay and hypothesized that, in a manner similar to EBV Zta, KSHV K-bZIP may play a role in this process. Since G1 arrest is favored after lytic replication, we sought to investigate whether any other immediate-early genes besides K-bZIP was involved in cell cycle arrest. Because of the conservation of the splicing event, we hypothesized that the rta gene of MHV-68 undergoes similar RNA processing. Interestingly, mutation of a conserved DRY amino acid sequence to VRY, as found in vGPCR, was sufficient to induce constitutive signalling of CXCR2 and induce oncogenic transformation (Burger et al. A significant (p < 0.01, paired Student’s t test) difference was found between animals treated with DISC/mGM-CSF and media. In comparison, the consequences of almost-instantaneous activation of STAT3 are not well-understood other than the critical role of EBV-activated STAT3 in rapidly crippling the DNA damage response (DDR) in B cells (described below). While this recombinant displayed increased entry kinetics on hepatocytes, wild-type HSV-1 entry was even more efficient than the recombinant, indicating that the preferred mode of entry in these cells was mediated by an interaction of gD with one or more of the natural receptors present on hepatocytes. (B) Expression of MEQ protein as determined by Western blotting. HHV-6A- or mock-infected Molt3 cells, with or without PFA, were harvested at 24 h post-infection (pi), fixed, and subjected to IFA using antibodies against U14 and EDD (A) or gQ1(B); nuclear DNA was counterstained with Hoechst 33342. The bars represent findings in samples from four different patients, two with AML and two with ALL. Figure 2. ORF50 mRNA expressed in BC-3 cells following infection with HSV-1. Therefore, this infection was performed by infecting with 10 PFU and multiplying the resulting ∼200 plaques by 10. Sucrose gradient ultracentrifugation.Continuous 0 to 10% sucrose gradients were prepared using a Gradient Master instrument (Biocomp, Fredericton, New Brunswick, Canada) with sucrose gradient buffer (SGB) (10 mM Tris [pH 8.0], 1.5 mM MgCl2, and 0.5 M EGTA) containing 450 mM NaCl. Nocodazole treatment causes G2/M-arrest in BJAB cells (Fig. Nucleotide and amino acid sequences of p78. From the second passage on, the virus undergoing selection was harvested at a 4+ CPE or when cells showed signs of drug-induced toxicity, whichever occurred first. Cells were grown to confluence by maintaining them in DMEM-H with 10% CS for 4 days after plating in 100-mm dishes and then released into cell cycle by replating at a lower density (8 × 105 cells/dish) in fresh DMEM-H with 10% CS on 100-mm dishes. Supernatants were stored at −70°C. In the case of transcriptional activation studies with TPA, we could not use an internal standard for transfection variation by using a second reporter gene since TPA activates the normalization promoter. 2A). A 1-kb ladder (Gibco BRL) and λHindIII were 5′ end labeled with [γ-32P]dATP, glyoxalated, and loaded onto the gels as the size standards. cDNA derived from cells that were mock-infected or inoculated with 1000 particles/cell of entry-defective ΔgB, ΔgD and ΔgH virions was used for real-time PCR analysis. HSV-1 1764/27-/4-/P1-/P2-/CMVGFP/27 is like 1764/27-/4-/P2- (described in reference 35) with the additional deletion of LAP1 sequences (nucleotides 6151 to 8366 and 113273 to 120470) and the insertion of a CMV GFP cassette so as to replace ICP27 and one LAT region between nucleotides 113273 and 120470. RTA expression was induced following treatment with 1 μg/ml doxycycline hyclate for the indicated times. We considered the possibility that decreased reactivation from latency after the passive transfer of antiviral antibody was due to effects of antibody in the ex vivo reactivation assay rather than in vivo effects relevant to the control of viral latency. Herpesviruses encode proteins that use these, as well as other novel (direct and indirect) mechanisms to inhibit Rb family member function (Figure 1 ). Unless otherwise specified, cell monolayers were infected with multiplicities of infection (MOI) between 5 and 20 PFU per cell and the infections were maintained at 37°C in DMEM containing 5% newborn calf serum for the times indicated in the text. Expression constructs and transfection.Mammalian expression constructs for EBV (strain B95-8), HSV-1 (strain 17), and CMV (strain Ad169) were prepared by PCR amplification of predicted open reading frames (ORF) and subsequent insertion into the multiple cloning site of the PMZS3F vector as previously described (23). The cell pellet was diluted serially with cold PBS and added to new Vero cell monolayers, which were then covered with maintenance medium-0.5% methylcellulose and incubated for plaque assay. Eisenberg and G. Virally encoded transactivator genes are repressed during latency, but when they are expressed, the transactivator proteins drive the lytic cycle. Furthermore, recent studies have suggested that HHV-6A and HHV-6B infection can also alter E2F1/Rb pathways and cause cell cycle arrest in the G2/M phase in infected SupT1 T cells (30) and that HHV-6B infection of MOLT 3 cells causes cell cycle arrest at the G1 phase concomitant with p53 phosphorylation and accumulation (36).