Novel less-abundant viral microRNAs encoded by herpes simplex virus 2 latency-associated transcript and their roles in regulating ICP34.5 and ICP0 mRNAs.
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.
Tang
Shuang
S
Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892-4555, USA.
Patel
Amita
A
Krause
Philip R
PR
D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D015342:DNA Probes; D015967:Gene Expression Regulation, Viral / Q000235:genetics*; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D014158:Transcription, Genetic; D044767:Ubiquitin-Protein Ligases / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics*
D015342:DNA Probes; D017874:Immediate-Early Proteins; C477254:LAT protein, Human herpesvirus 2; D035683:MicroRNAs; D012333:RNA, Messenger; D012367:RNA, Viral; D014764:Viral Proteins; C066469:gamma 34.5 protein, Human herpesvirus 1; D044767:Ubiquitin-Protein Ligases; C051804:Vmw110 protein, Human herpesvirus 1