%0 Journal Article %A Teng, Man %A Yu, Zu-Hua %A Zhao, Pu %A Zhuang, Guo-Qing %A Wu, Zi-Xiang %A Dang, Lu %A Li, Hui-Zhen %A Ma, Sheng-Ming %A Cui, Zhi-Zhong %A Zhang, Gai-Ping %A Wu, Run %A Luo, Jun %T Putative roles as oncogene or tumour suppressor of the Mid-clustered microRNAs in Gallid alphaherpesvirus 2 (GaHV2) induced Marek’s disease lymphomagenesis %D 2017 %J Journal of General Virology, %V 98 %N 5 %P 1097-1112 %@ 1465-2099 %R https://doi.org/10.1099/jgv.0.000786 %K miRNA %K miR-155 %K GaHV2 %K oncogene %K herpesvirus %K tumour suppressor %K Marek's disease virus %I Microbiology Society, %X In the last decade, numerous microRNAs (miRNAs) have been identified in diverse virus families, particularly in herpesviruses. Gallid alphaherpesvirus 2 (GaHV2) is a representative oncogenic alphaherpesvirus that induces rapid-onset T-cell lymphomas in its natural hosts, namely Marek’s disease (MD). In the GaHV2 genome there are 26 mature miRNAs derived from 14 precursors assembled into three clusters, namely the Meq-cluster, Mid-cluster and LAT-cluster. Several GaHV2 miRNAs, especially those in the Meq-cluster (e.g. miR-M4-5p), have been demonstrated to be critical in MD pathogenesis and/or tumorigenesis. Interestingly the downstream Mid-cluster is regulated and transcribed by the same promoter as the Meq-cluster in the latent phase of the infection, but the role of these Mid-clustered miRNAs in GaHV2 biology remains unclear. We have generated the deletion mutants of the Mid-cluster and of its associated individual miRNAs in GX0101 virus, a very virulent GaHV2 strain, and demonstrated that the Mid-clustered miRNAs are not essential for virus replication. Using GaHV2-infected chickens as an animal model, we found that, compared with parental GX0101 virus, the individual deletion of miR-M31 decreased the mortality and gross tumour incidence of infected chickens while the deletion individually of miR-M1 or miR-M11 unexpectedly increased viral pathogenicity or oncogenicity, similarly to the deletion of the entire Mid-cluster region. More importantly, our data further confirm that miR-M11-5p, the miR-M11-derived mature miRNA, targets the viral oncogene meq and suppresses its expression in GaHV2 infection. We report here that members of the Mid-clustered miRNAs, miR-M31-3p and miR-M11-5p, potentially act either as oncogene or tumour suppressor in MD lymphomagenesis. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.000786