These observations mimic those made previously with HSV-1 in human trigeminal ganglia and confirm the recent findings during latency in HSV-2-infected mice and guinea pigs. These data demonstrate the ability of a second HSV type to infect the same anatomic region and illustrate the difference in reactivation frequency of the two types in the same person. light to prevent gene expression did not reactivate HSV-2. 10, Rrn. Moving walls are generally represented in years. HSV2-LAT-S1 was impaired for reactivation in the guinea pig genital model, while its rescuant and HSV2-LAT-P1 reactivated with a wild-type HSV-2 phenotype. The replication of these viruses in the mouse eye and their spread to TG and brains were similar.
Furthermore, a similar half-life was measured for the 2-kb LAT in transiently transfected nonneuronal monkey COS-1 cells, suggesting that the stability of the 2-kb LAT is neither cell type nor species specific. The viral genome translocates to the nucleus, where it establishes a specialized infection known as latency, re-emerging periodically to seed new infections. Understanding the molecular mechanism of latency (establishment, maintenance and reactivation) will set the groundwork required to develop effective therapies. The ability of ICP4 to suppress ICP34.5-targeting miRNAs and to activate lytic viral genes suggests that ICP4 could play a key role in the switch between latency and reactivation. Nevertheless, viral mutants that are defective for viral replication can establish a latent infection, albeit with reduced efficiency (8, 9, 13, 15, 18, 23, 28, 34). ICP10DeltaPK was also compromised for growth and disease causation in this model. We infected mice with LAT-deficient or LAT-restored HSV-2 at a wide range of inocula.
The replication of these viruses in the mouse eye and their spread to TG and brains were similar. After latency is established, a proper stimulus causes reactivation; virus becomes evident at mucocutaneous sites, appearing as skin vesicles or mucosal ulcers (Fig. Infection of neuro-2A cells with dLAT2903 also led to higher levels of IFN-β promoter activity than in cells infected with wild-type (wt) HSV-1. Although LAT inhibits caspase 3 activation, the signalling pathway by which LAT inhibits caspase 3 activation was not identified. To pursue this question, we inserted the gene for the enhanced green fluorescent protein (EGFP) under control of the LAT promoter in a LAT-negative virus (ΔLAT-EGFP) and in a LAT-positive virus (LAT-EGFP). To explore whether the RL1 fragment of the five adjacent miRNAs has an effect on cell apoptosis, then provide supporting evidence to elucidate the potential role of these miRNAs and to aid screening of their cellular targets. Infectious virus was recovered from the ganglia of chronically infected tree shrews.
Here, we examined the role of COX-2 in the induction of ICs, GFs, angiogenesis and invasive events occurring during KSHV de novo infection of endothelial cells. Guinea pigs infected with NotPolyA experienced reduced neurological complications of acute infection relative to those infected with the rescuant, but the recurrence phenotype of the NotPolyA mutant was similar to those of its rescuant and wild-type HSV-2, indicating that reduction of miR-H6 expression is not by itself able to alter the establishment of latency for the wild-type virus or the recurrence phenotype. Jones, J. In addition, caspase 8-induced apoptosis was specifically inhibited in cells expressing the Pst-Mlu LAT fragment. Treatment with the immunomodulator appeared to inhibit or reduce HSV infection early in viral pathogenesis in all three model systems, producing protection from clinical disease and resulting in less virus to induce a systemic antibody response, with either a reduction in latent virus infection or no enhancement of development of latency. It is unknown whether this also occurs in humans and it may be an artifact due to the animal species, route of inoculation or the large virus inoculum used in experimental models. 2.
However, it is not yet clear whether this is a direct effect on the reactivation process per se or, as we have suggested, an indirect effect resulting from a decreased efficiency of establishment of latent infections. To detect apoptotic CD8+ T cells, sections were assayed by TUNEL and stained for CD8+ T cells. By transfecting cells with a construct expressing the Pst-Mlu segment of the LAT, encompassing the LAT exon 1, the stable 2.0-kb intron, and 5′ part of exon 2, we confirmed that this region was able to diminish the onset of programmed cell death initiated by anti-Fas and camptothecin treatment. We found that in lytically infected cells and in acutely infected mouse ganglia, expression of LAT-encoded microRNAs was weak and unaffected by a deletion that includes the LAT promoter. In mice, LAT-negative mutants appear to establish latency in fewer neurons than does wild-type HSV-1. LAT inhibits apoptosis and maintains latency by promoting the survival of infected neurons4. In sensory neurons it establishes a silent (latent) infection.
Using Northern hybridization analyses of RNA isolated from transiently transfected SY5Y cells over time after repression of LAT expression, we measured the half-life of the 2-kb LAT to be approximately 24 h.