MicroRNA profiling in the bursae of Marek's disease virus-infected resistant and susceptible chicken lines.

Marek's disease (MD) is a lymphoproliferative disease of domestic chickens caused by a cell-associated oncogenic alpha-herpesvirus, Marek's disease virus (MDV). Clinical signs of MD include bursal/thymic atrophy, neurologic disorders, and T cell lymphomas. MiRNAs play key roles in regulation of gene expression by targeting translational suppression or mRNA degradation. MDV encodes miRNAs that are associated with viral pathogenicity and oncogenesis. In this study, we performed miRNA sequencing in the bursal tissues, non-tumorous but viral-induced atrophied lymphoid organ, from control and infected MD-resistant and susceptible chickens at 21 days post infection. In addition to some known miRNAs, a minimum of 300 novel miRNAs were identified in each group that mapped to the chicken genome with no sequence homology to existing miRNAs in chicken miRbase. Comparative analysis identified 54 deferentially expressed miRNAs between the chicken lines that might shed light on underlying mechanism of bursal atrophy and resistance or susceptibility to MD. • MDV induces bursal atrophy and visceral tumors. • Comparative analysis of small RNA gene expression profiling identified more than 300 novel chicken miRNAs. • 54 differentially expressed known and novel miRNAs were identified between the control and infected chicken lines. • First report of its kind on miRNA profiling in a non-tumorous lymphoid organ that undergoes severe atrophy in MDV-infected chickens. • Complementary miRNA profiling in thymus might shed light on the role of miRNA in tumor development and lymphoid atrophy. [ABSTRACT FROM AUTHOR]