Alternative splicing of the latency-related transcript of bovine herpesvirus 1 yields RNAs containing unique open reading frames.
The latency-related transcript (LRT) of bovine herpesvirus 1 (BHV-1) is the only abundant viral RNA detected during latency. A previous study (A. Hossain, L. M. Schang, and C. Jones, J. Virol. 69:5345-5352, 1995) concluded that splicing of polyadenylated [poly(A)+] and splicing of nonpolyadenylated [poly(A)-] LRT are different. In this study, splice junction sites of LRT were identified. In trigeminal ganglia of acutely infected calves (1, 7, or 15 days postinfection [p.i.]) or in latently infected calves (60 days p.i.), alternative splicing of poly(A)+ LRT occurred. Productive viral gene expression in trigeminal ganglia is readily detected from 2 to 7 days p.i. but not at 15 days p.i. (L. M. Schang and C. Jones, J. Virol. 71:6786-6795, 1997), suggesting that certain aspects of a lytic infection occur in neurons and that these factors influence LRT splicing. Splicing of poly(A)- LRT was also detected in transfected COS-7 cells or infected MDBK cells. DNA sequence analysis of spliced LRT cDNAs, poly(A)+ or poly(A)-, revealed nonconsensus splice signals at exon/intron and intron/exon boundaries. The GC-AG splicing signal utilized by the herpes simplex virus type 1 latency-associated transcript in latently infected mice is also used by LRT in latently infected calves. Taken together, these results led us to hypothesize that (i) poly(A)+ LRT is spliced in trigeminal ganglia by neuron-specific factors, (ii) viral or virus-induced factors participate in splicing, and (iii) alternative splicing of LRT may result in protein isoforms which have novel biological properties.
Center for Biotechnology, Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0905, USA.
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D017398:Alternative Splicing; D000818:Animals; D019556:COS Cells; D002417:Cattle; D002460:Cell Line; D003001:Cloning, Molecular; D005784:Gene Amplification; D007242:Herpesvirus 1, Bovine / Q000235:genetics* / Q000502:physiology; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D012367:RNA, Viral; D017423:Sequence Analysis, RNA; D014162:Transfection; D017735:Virus Latency
D012367:RNA, Viral