Novel less-abundant viral microRNAs encoded by herpes simplex virus 2 latency-associated transcript and their roles in regulating ICP34.5 and ICP0 mRNAs

J Virol. 2009 Feb;83(3):1433-42. doi: 10.1128/JVI.01723-08. Epub 2008 Nov 19.

Abstract

We recently identified an acutely and latently expressed viral microRNA (miRNA), miR-I, encoded by herpes simplex virus 2 (HSV-2) latency-associated transcript (LAT) through small RNA cloning and two miRNAs encoded by HSV-1 LAT through prediction. We now report the use of high-throughput sequencing technology to identify two additional relatively less-abundant viral miRNAs, miR-II and miR-III, encoded by HSV-2 LAT exon 2. miR-II includes two miRNAs, miR-II-5p and miR-II-3p, which are processed from the same miRNA precursor. miR-II and miR-III map antisense to the 5' untranslated region of ICP34.5 and to the coding region of ICP0 exon 3, respectively. These novel miRNAs are conserved in different HSV-2 strains, and their presence in infected- and transfected-cell cultures was confirmed by Northern hybridization. All three HSV-2 LAT-encoded miRNAs map to genome locations similar to those of three out of four identified HSV-1 LAT-encoded miRNAs, but the sequences of these miRNAs are not conserved. The expression of LAT-encoded miRNAs is negatively regulated by ICP4, the major viral transactivator. We further show that, similar to miR-I, miR-II is able to efficiently silence the expression of ICP34.5, a key viral neurovirulence factor, and that miR-III is able to silence the expression of ICP0, a key viral transactivator. All these data suggest that LAT sequences likely contribute to HSV latency and reactivation through tight control of these LAT-encoded miRNAs and their viral targets.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Base Sequence
  • Blotting, Northern
  • Cell Line
  • DNA Probes
  • Gene Expression Regulation, Viral / genetics*
  • Humans
  • Immediate-Early Proteins / genetics*
  • MicroRNAs / genetics*
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic
  • RNA, Messenger / genetics*
  • RNA, Viral / genetics*
  • Transcription, Genetic
  • Ubiquitin-Protein Ligases / genetics*
  • Viral Proteins / genetics*

Substances

  • DNA Probes
  • Immediate-Early Proteins
  • LAT protein, Human herpesvirus 2
  • MicroRNAs
  • RNA, Messenger
  • RNA, Viral
  • Viral Proteins
  • gamma 34.5 protein, Human herpesvirus 1
  • Ubiquitin-Protein Ligases
  • Vmw110 protein, Human herpesvirus 1