Using PAR-CLIP, a technology which allows the direct and transcriptome-wide identification of miRNA targets, we delineate the target sites for all viral and cellular miRNAs expressed in PEL cell lines. The resulting data set revealed that KSHV miRNAs directly target more than 2000 cellular mRNAs, including many involved in pathways relevant to KSHV pathogenesis. Moreover, 58% of these mRNAs are also targeted by EBV miRNAs, via distinct binding sites.Clusters with seed matches to expressed miRNAs were considered candidate target sites. Of the clusters mapping to human 3'UTRs, 69% (BC-1) and 70% (BC-3) had seed matches to expressed miRNAs (Tables S6).Table S6A BC-1 derived 3'UTR clusters with seed matches to expressed miRNAs.
Our HITS-CLIP data yield 1185 human 3'UTRs targeted by members of the miR-17~92 cluster in Jijoye cells. Comparison to the 1664 3'UTRs targeted by EBV miRNAs reveals 740 shared genes (44% of EBV targets and 62% of miR-17~92 targets; Figure 6B and Supplementary Table 7). Thus, EBV miRNAs co-target a majority of miR-17~92 regulated mRNAs, which are assigned to a variety of pathways, most notably regulating transcription, apoptosis, and the cell cycle (Figure 6C). Similarly, other abundant immunologically relevant miRNAs, 142-3p and miR-155, co-target with EBV miRNAs a large fraction of their Ago-bound 3'UTRs, representing ~60% of the targets for each of these host miRNAs (Supplementary Figure 5).
