Herpes simplex virus (HSV) persists in its human

Herpes simplex virus 1 (HSV-1) replicates in the nucleus of host cells and radically alters nuclear architecture as part of its replication process. Replication compartments (RCs) form, and host chromatin is marginalized. Chromatin is later dispersed, and RCs spread past it to reach the nuclear edge. Using a lamin A-green fluorescent protein fusion, we provide direct evidence that the nuclear lamina is disrupted during HSV-1 infection and that the UL31 and UL34 proteins are required for this. We show nuclear expansion from 8 h to 24 h postinfection and place chromatin rearrangement and disruption of the lamina in the context of this global change in nuclear architecture. We show HSV-1-induced disruption of the localization of Cdc14B, a cellular protein and component of a putative nucleoskeleton. We also show that UL31 and UL34 are required for nuclear expansion. Studies with inhibitors of globular actin (G-actin) indicate that G-actin plays an essential role in nuclear expansion and chromatin dispersal but not in lamina alterations induced by HSV-1 infection. From analyses of HSV infections under various conditions, we conclude that nuclear expansion and chromatin dispersal are dispensable for optimal replication, while lamina rearrangement is associated with efficient replication.Herpes simplex virus 1 (HSV-1) forms replication compartments (RCs) in the infected cell nucleus (32), in which DNA replication, late viral transcription, and viral nucleocapsid assembly occur. In doing so, the virus causes cytopathic effects by affecting factors that control nuclear architecture: host cell chromatin and the nuclear lamina (5,24,34,40,41). During infection, RCs form from small prereplicative sites and expand into large globular domains, disrupting the nuclear interior by compressing and marginalizing host chromatin (24,39,44,45). Following assembly, nucleocapsids are thought to exit the nucleus by budding at the inner nuclear membrane into the perinuclear space (11). This requires that nucleocapsids move through the host chromatin layer and the nuclear lamina to reach the membrane. Thus, HSV-1 manipulates the nuclear interior and periphery to achieve replication and egress.Several studies have described changes in the nuclear lamina during infection with different herpesviruses (9,25,34,40,41). Mouse cytomegalovirus has been shown to disrupt the nuclear lamina, and two viral proteins, UL50 and UL53, have been implicated in this process (25). Homologues of these proteins appear to be present in several other viruses, including HSV-1, HSV-2, pseudorabies virus, and Epstein-Barr virus (EBV) (19,21,25,35,51). In EBV, the proteins BFLF2 and BFRF1 have been shown to interact and colocalize at the nuclear membrane, and BFRF1 binds to lamin B in vitro (9, 21). A mutant EBV lacking a functional BFRF1 gene is defective for replication in several cell lines and shows accumulation of nucleocapsids in the nucleus of infected cells (6). The homologous pseudorabies virus UL31 and UL34 proteins have been shown to interact with one ano...

Herpes simplex virus 2 (HSV-2), the principal causative agent of recurrent genital herpes, is a highly prevalent viral infection worldwide. Limited information is available on the amount of genomic DNA variation between HSV-2 strains because only two genomes have been determined, the HG52 laboratory strain and the newly sequenced SD90e low-passage-number clinical isolate strain, each from a different geographical area. In this study, we report the nearly complete genome sequences of 34 HSV-2 lowpassage-number and laboratory strains, 14 of which were collected in Uganda, 1 in South Africa, 11 in the United States, and 8 in Japan. Our analyses of these genomes demonstrated remarkable sequence conservation, regardless of geographic origin, with the maximum nucleotide divergence between strains being 0.4% across the genome. In contrast, prior studies indicated that HSV-1 genomes exhibit more sequence diversity, as well as geographical clustering. Additionally, unlike HSV-1, little viral recombination between HSV-2 strains could be substantiated. These results are interpreted in light of HSV-2 evolution, epidemiology, and pathogenesis. Finally, the newly generated sequences more closely resemble the low-passage-number SD90e than HG52, supporting the use of the former as the new reference genome of HSV-2. IMPORTANCEHerpes simplex virus 2 (HSV-2) is a causative agent of genital and neonatal herpes. Therefore, knowledge of its DNA genome and genetic variability is central to preventing and treating genital herpes. However, only two full-length HSV-2 genomes have been reported. In this study, we sequenced 34 additional HSV-2 low-passage-number and laboratory viral genomes and initiated analysis of the genetic diversity of HSV-2 strains from around the world. The analysis of these genomes will facilitate research aimed at vaccine development, diagnosis, and the evaluation of clinical manifestations and transmission of HSV-2. This information will also contribute to our understanding of HSV evolution. Herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2) are two closely related human species of herpesviruses in the genus Simplexvirus of the family Herpesviridae (1). HSV-1 is mostly associated with orofacial infections, while HSV-2 is generally associated with genital herpes. Both viruses cause significant human disease, so knowledge of the structure of their DNA genomes and the extent of their genetic variation is very important. A high overall GC content and the presence of highly reiterated repeat regions in both noncoding and coding portions of the genome complicate sequence determination (2).The HSV linear double-stranded DNA genomes consist of two covalent linked components, the long (L) and short (S) components, which invert relative to each other by intramolecular recombination (1). The L component consists of unique sequences (U L ) bounded by inverted repeats (R L and R L =), and the S component consists of unique sequences (U S ) bounded by inverted repeats (R S and R S =) (3). The termini con...

The clinical signs and symptoms of acute respiratory tract infections (RTIs) are not pathogen specific. Highly sensitive and specific nucleic acid amplification tests have become the diagnostic reference standard for viruses, and translation of bacterial assays from basic research to routine clinical practice represents an exciting advance in respiratory medicine. Most recently, molecular diagnostics have played an essential role in the global health response to the novel coronavirus pandemic. How best to use newer molecular tests for RTI in combination with clinical judgment and traditional methods can be bewildering given the plethora of available assays and rapidly evolving technologies. Here, we summarize the current state of the art with respect to the diagnosis of viral and bacterial RTIs, provide a practical framework for diagnostic decision making using selected patient-centered vignettes, and make recommendations for future studies to advance the field.