title: Kinetic expression analysis of the cluster mdv1-mir-M9-M4, genes meq and vIL-8 differs between the lytic and latent phases of Marek's disease virus infection.
abstract: Marek's disease virus (GaHV-2) is an alphaherpesvirus that induces T-cell lymphoma in chickens. The infection includes both lytic and latent stages. GaHV-2 encodes three clusters of microRNAs (miRNAs) located in the internal (I)/terminal (T) repeat (R) regions. We characterized transcripts encompassing the mdv1-mir-M9-M4 and mir-M11-M1 clusters located in the IR(L)/TR(L) region, upstream and downstream from the meq oncogene, respectively. By 5'- and 3'-RACE-PCR and targeted RT-PCR, we showed that mdv1-mir-M9-M4 could be transcribed from an unspliced transcript or from at least 15 alternatively spliced transcripts covering the IR(L)/TR(L) region, encompassing the meq and vIL-8 genes and localizing the mdv1-mir-M9-M4 cluster to the first intron at the 5'-end. However, all these transcripts, whether spliced or unspliced, seemed to start at the same transcriptional start site, their transcription being driven by a single promoter, prmiRM9M4. We demonstrated alternative promoter usage for the meq and vIL-8 genes, depending on the phase of GaHV-2 infection. During the latent phase, the prmiRM9M4 promoter drove transcription of the meq and vIL-8 genes and the mdv1-mir-M9-M4 cluster in the first intron of the corresponding transcripts. By contrast, during the lytic phase, this promoter drove the transcription only of the mdv1-mir-M9-M4 cluster to generate unspliced mRNA, the meq and vIL-8 genes being transcribed principally from their own promoters. Despite the expression of meq and the mdv1-mir-M9-M4 cluster under two different transcriptional processes during the latent and lytic phases, our data provide an explanation for meq expression and mdv1-mir-M4-5P overexpression in miRNA libraries from GaHV-2-infected cells, regardless of the phase of infection.
authors.affiliation: Equipe Transcription et Lymphome Viro-Induit (TLVI), Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.
authors.forename: D
authors.initials: D
authors.lastname: Coupeau
authors.affiliation: INRA-Département de Santé Animale, Centre de recherches de Tours, 37380 Nouzilly, France.|Equipe Transcription et Lymphome Viro-Induit (TLVI), Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.
authors.forename: G
authors.initials: G
authors.lastname: Dambrine
authors.affiliation: Equipe Transcription et Lymphome Viro-Induit (TLVI), Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.
authors.forename: D
authors.initials: D
authors.lastname: Rasschaert
mesh_terms: D000818:Animals; D002645:Chickens; D020869:Gene Expression Profiling; D015967:Gene Expression Regulation, Viral; D007700:Kinetics; D025922:Mardivirus / Q000235:genetics*; D008380:Marek Disease / Q000821:virology*; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics; D009856:Oncogene Proteins, Viral / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D017735:Virus Latency
chemical_list: C100369:Eco-Q protein, Gallid herpesvirus 2; D035683:MicroRNAs; D009856:Oncogene Proteins, Viral; C559372:vIL-8 protein, Marek's disease virus