A structural and functional comparison of the latency-associated transcript promoters of herpes simplex virus type 1 strains KOS and McKrae

Strelow, Lisa; Laycock, Keith A.; Jun, Patricia Y.; Rader, Katherine; Brady, Robert H.; Miller, Judith Kelvin; Pepose, Jay S.; Leib, David A.

doi:10.1099/0022-1317-75-9-2475

Cited by 17 publications

(19 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our initial investigations of the LAT-dependent establishment function were performed with HSV-1 strain KOS/M (59,79), which reactivates less well in vivo than some other strains (25,59,60,71). We therefore sought to confirm and extend our previous results with HSV-1 strain 17synϩ, which reactivates with high efficiency in the murine hyperthermic stress (HS) model (56,(58)(59)(60).…”

mentioning

confidence: 60%

“…KOS is less neuroinvasive than most other HSV-1 strains (76). Further, strain KOS establishes latent infections that contain fewer viral genome copies than either strain 17synϩ or McKrae (58) and also reactivates in vivo less efficiently in the rabbit (25,72) and in the mouse following UV light (71) or HS induction (58)(59)(60)79). It was therefore important to demonstrate that the reduced establishment of the latency phenotype of KOS-based LAT null mutants was not unique to this strain but was also evident in the genetic background of a more virulent HSV-1 strain, such as 17synϩ.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Herpes Simplex Virus Type 1 Latency-Associated Transcript Gene Promotes Neuronal Survival

Thompson

Sawtell

2001

J Virol

218

264

View full text Add to dashboard Cite

A complex interaction has evolved between the host's peripheral nervous system (PNS) and herpes simplex virus type 1 (HSV-1). Sensory neurons are permissive for viral replication, yet the virus can also enter a latent state in these cells. The interplay of viral and neuronal signals that regulate the switch between the viral lytic and latent states is not understood. The latency-associated transcript (LAT) regulates the establishment of the latent state and is required for >65% of the latent infections established by HSV-1 (R. L. Thompson and N. M. Sawtell, J. Virol. 71:5432-5440, 1997). To further investigate how LAT functions, a 1.9-kb deletion that includes the entire LAT promoter and 827 bp of the 5 end of the primary LAT mRNA was introduced into strain 17syn؉. The wild-type parent, three independently derived deletion mutants, and two independently derived genomically rescued variants of the mutants were analyzed in a mouse ocular model. The number of latent sites established in trigeminal ganglion (TG) neurons was determined using a single-cell quantitative PCR assay for the viral genome on purified TG neurons. It was found that the LAT null mutants established ϳ75% fewer latent infections than the number established by the parental strain or rescued variant. The reduced establishment phenotype of LAT null mutants was due at least in part to a dramatic increase in the loss of TG neurons in animals infected with the LAT mutants. Over half of the neurons in the TG were destroyed following infection with the LAT mutants, and this was significantly more than were lost following infection with wild type. This is the first demonstration that the HSV LAT locus prevents the destruction of sensory neurons. The death of these neurons did not appear to be the result of increased apoptosis as measured by a terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay. Animals latently infected with the LAT null mutants reactivated less frequently in vivo and this was consistent with the reduction in the number of neurons in which latency was established. Thus, one function of the LAT gene is to protect sensory neurons and enhance the establishment of latency in the PNS.A complex interaction between the virus and the host determines the fate of cells infected by herpes simplex virus type 1 (HSV-1). At the body surface, about 77 known viral lyticphase genes are actively transcribed during productive infection, which is invariably lethal for the cell. Latent infections are characterized by the down regulation of these lytic-phase genes in innervating sensory neurons of the trigeminal ganglia (TG), and these cells survive infection. The continued expression of the latency-associated transcript (LAT) is detectable by in situ hybridization in about 100 to 200 sensory neurons per mouse TG (for review, see references 1 and 87). The discovery of the LAT RNAs over a decade ago led to speculation that that they must play a central role in viral latency (70), but the function(s) of the LAT gene is not yet unde...

show abstract

mentioning

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Herpes Simplex Virus Type 1 Latency-Associated Transcript Gene Promotes Neuronal Survival

Thompson

Sawtell

2001

J Virol

218

264

View full text Add to dashboard Cite

show abstract

“…Another HSV-1 strain, McKrae, was isolated from a patient with herpes simplex keratitis (Williams et al, 1965), and passaged an unknown number of times in tissue culture. McKrae undergoes spontaneous or induced reactivation at a higher frequency and is among the most virulent HSV-1 strains in animal models (Hill et al, 1987; Perng et al, 2002; Sawtell et al, 1998; Strelow et al, 1994). …”

mentioning

confidence: 99%

HSV-1 strain McKrae is more neuroinvasive than HSV-1 KOS after corneal or vaginal inoculation in mice

2013

View full text Add to dashboard Cite

Strains of HSV-1 have been noted to vary in their pathogenesis. We compared the replication of strains KOS and McKrae in mice by two routes of infection, ocular and vaginal. Peripheral replication of KOS was similar (cornea) or attenuated over time (vagina) compared with McKrae; however, McKrae replicated in the nervous system to significantly higher levels than KOS after inoculation by either route. Host genetic background strongly influenced the capacity for virus entry into the nervous system from the vagina. KOS and McKrae replicated equivalently after intracranial inoculation, indicating that McKrae’s pathogenic phenotype is linked to neuroinvasiveness rather than neurovirulence.

show abstract

“…Other methods, like quantitative PCR, can also be utilized to look at viral gene expression patterns that precede GFP-expression, since GFP is expressed as a “true-late” gene, or for virus strains that lack a reporter gene. In addition, our neuronal cell culture system can also be used with different HSV-1 strains, regardless of their neuroinvasive potential or ability to regulate the host immune response (10–13). Finally, the in vitro culture system described here can be applied to other neuronal cell types and ex vivo peripheral ganglia cultures obtained from higher order species, including humans (14,15).…”

Section: Discussionmentioning

confidence: 99%

A Primary Neuron Culture System for the Study of Herpes Simplex Virus Latency and Reactivation

Kobayashi

Kim

Camarena

et al. 2012

JoVE

View full text Add to dashboard Cite

Herpes simplex virus type-1 (HSV-1) establishes a life-long latent infection in peripheral neurons. This latent reservoir is the source of recurrent reactivation events that ensure transmission and contribute to clinical disease. Current antivirals do not impact the latent reservoir and there are no vaccines. While the molecular details of lytic replication are well-characterized, mechanisms controlling latency in neurons remain elusive. Our present understanding of latency is derived from in vivo studies using small animal models, which have been indispensible for defining viral gene requirements and the role of immune responses. However, it is impossible to distinguish specific effects on the virus-neuron relationship from more general consequences of infection mediated by immune or non-neuronal support cells in live animals. In addition, animal experimentation is costly, time-consuming, and limited in terms of available options for manipulating host processes. To overcome these limitations, a neuron-only system is desperately needed that reproduces the in vivo characteristics of latency and reactivation but offers the benefits of tissue culture in terms of homogeneity and accessibility. Here we present an in vitro model utilizing cultured primary sympathetic neurons from rat superior cervical ganglia (SCG) (Fig. 1) to study HSV-1 latency and reactivation that fits most if not all of the desired criteria. After eliminating non-neuronal cells, near-homogeneous TrkA+ neuron cultures are infected with HSV-1 in the presence of acyclovir (ACV) to suppress lytic replication. Following ACV removal, non-productive HSV-1 infections that faithfully exhibit accepted hallmarks of latency are efficiently established. Notably, lytic mRNAs, proteins, and infectious virus become undetectable, even in the absence of selection, but latency-associated transcript (LAT) expression persists in neuronal nuclei. Viral genomes are maintained at an average copy number of 25 per neuron and can be induced to productively replicate by interfering with PI3-Kinase/Akt signaling or the simple withdrawal of nerve growth factor (1). A recombinant HSV-1 encoding EGFP fused to the viral lytic protein Us11 provides a functional, real-time marker for replication resulting from reactivation that is readily quantified. In addition to chemical treatments, genetic methodologies such as RNA-interference or gene delivery via lentiviral vectors can be successfully applied to the system permitting mechanistic studies that are very difficult, if not impossible, in animals. In summary, the SCG-based HSV-1 latency/reactivation system provides a powerful, necessary tool to unravel the molecular mechanisms controlling HSV1 latency and reactivation in neurons, a long standing puzzle in virology whose solution may offer fresh insights into developing new therapies that target the latent herpesvirus reservoir.

show abstract

A structural and functional comparison of the latency-associated transcript promoters of herpes simplex virus type 1 strains KOS and McKrae

Abstract: The promoters of the latency-associated transcripts (LATs)

Cited by 17 publications

References 28 publications

Herpes Simplex Virus Type 1 Latency-Associated Transcript Gene Promotes Neuronal Survival

Herpes Simplex Virus Type 1 Latency-Associated Transcript Gene Promotes Neuronal Survival

HSV-1 strain McKrae is more neuroinvasive than HSV-1 KOS after corneal or vaginal inoculation in mice

A Primary Neuron Culture System for the Study of Herpes Simplex Virus Latency and Reactivation

Contact Info

Product

Resources

About