MiRNA expression signatures induced by Marek's disease virus infection in chickens

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. Emerging evidence suggests that differential miRNA expression is associated with viral infection and cancer. Marek's disease virus infection induces lymphoma in chickens. However, the host defense response against Marek's disease (MD) progression remains poorly understood. Here, we utilized microarrays to screen miRNAs that were sensitive to Marek's disease virus (MDV) infection. QRT-PCR analysis confirmed the microarray data and revealed expression patterns of some miRNAs in tumor samples. Chicken miRNA gga-miR-15b, which was reduced in infected susceptible chickens and splenic tumors, controlled the expression of ATF2 (activating transcription factor 2). ATF2 was significantly increased in the same group. Our results indicated that differential expression of miRNA in resistant and susceptible chickens was caused by MDV infection, which effectively influenced protein expression of ATF2. This latter result might be related to Marek's disease resistance/susceptibility.