Background

nucleotide) regulatory non-coding RNAs that post-transcriptionally regulate gene expression by inhibiting the translation of mRNA transcripts or cleaving them [1-4]. MicroRNAs are encoded by cellular or viral genomes [5,6] and play a vital role in numerous cellular processes, in-cluding cell metabolism, viral infection, and antiviral im-mune response [7-9]. Indeed, a large number of miRNAs have been discov-ered in numerous organisms [1]. As an effective and economic regulatory strategy of gene expression, miR-NAs are employed by viruses to regulate the expression of their own genes, host genes, or both [10,11]. Most viral miRNAs have been identified by traditional cloning strategy from virus-infected cells [12-15], yet others hav