title: Regulation of the latency-reactivation cycle by products encoded by the bovine herpesvirus 1 (BHV-1) latency-related gene.
abstract: Like other α-herpesvirinae subfamily members, the primary site for bovine herpesvirus 1 (BHV-1) latency is ganglionic sensory neurons. Periodically BHV-1 reactivates from latency, virus is shed, and consequently virus transmission occurs. Transcription from the latency-related (LR) gene is readily detected in neurons of trigeminal ganglia (TG) of calves or rabbits latently infected with BHV-1. Two micro-RNAs and a transcript encompassing a small open reading frame (ORF-E) located within the LR promoter can also be detected in TG of latently infected calves. A BHV-1 mutant that contains stop codons near the beginning of the first open reading frame (ORF2) within the major LR transcript (LR mutant virus) has been characterized. The LR mutant virus does not express ORF2, a reading frame that lacks an initiating ATG (reading frame B), and has reduced expression of ORF1 during productive infection. The LR mutant virus does not reactivate from latency following dexamethasone treatment suggesting that LR protein expression regulates the latency-reactivation cycle. Higher levels of apoptosis occur in TG neurons of calves infected with the LR mutant viruses when compared to wild-type BHV-1 indicating that the anti-apoptotic properties of the LR gene is necessary for the latency-reactivation cycle. ORF2 inhibits apoptosis and regulates certain viral promoters, in part, because it interacts with three cellular transcription factors (C/EBP-alpha, Notch1, and Notch3). Although ORF2 is important for the latency-reactivation cycle, we predict that other LR gene products play a supportive role during life-long latency in cattle.
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, RM 234, Morisson Life Science Center, Lincoln, NE 68583, USA. cjones@unlnotes.unl.edu
authors.forename: Clinton
authors.initials: C
authors.lastname: Jones
authors.forename: Leticia Frizzo
authors.initials: LF
authors.lastname: da Silva
authors.forename: Devis
authors.initials: D
authors.lastname: Sinani
mesh_terms: D000305:Adrenal Cortex Hormones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000821:virology*; D003907:Dexamethasone / Q000494:pharmacology; D015967:Gene Expression Regulation, Viral; D006566:Herpesviridae Infections / Q000188:drug therapy / Q000662:veterinary* / Q000821:virology; D007242:Herpesvirus 1, Bovine / Q000235:genetics*; D009154:Mutation; D011401:Promoter Regions, Genetic; D011984:Sensory Receptor Cells / Q000821:virology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D012668:Trigeminal Ganglion / Q000821:virology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014775:Virus Activation / Q000187:drug effects; D017735:Virus Latency / Q000502:physiology*
chemical_list: D000305:Adrenal Cortex Hormones; D014157:Transcription Factors; D014764:Viral Proteins; C401822:latency-related protein, Bovine herpesvirus 1; D003907:Dexamethasone