Hepatitis C virus functionally sequesters miR-122 [LNAs vs Mock CLIP]

Hepatitis C virus uniquely requires the liver specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (Ago) during HCV infection showed robust Ago binding on the HCV 5’UTR, at known and predicted miR-122 sites. On the human transcriptome, we observed reduced Ago binding and functional mRNA de-repression of miR-122 targets during virus infection. This miR-122 “sponge” effect could be relieved and redirected to miR-15 targets by swapping the miRNA tropism of the virus. Single-cell expression data from reporters containing miR-122 sites showed significant de-repression during HCV infection depending on expression level and number of sites. We describe a quantitative mathematical model of HCV induced miR-122 sequestration and propose that such miR-122 inhibition by HCV RNA may result in global de-repression of host miR-122 targets, providing an environment fertile for the long-term oncogenic potential of HCV. AGO HITS-CLIP libraries were generated from mock, LNA or miravirsen treated, or from U3 virus electroporated Huh7.5 cells. Cells were harvested for CLIP 48 hours after small RNA treatment and 17 days after virus electroporation. LNA treatments for U3 virus infected cells was carried out for 48hours. Libraries were generated with a 4nt index read, a common priming sequence, followed by a 5nt degenerate barcode terminiating in a G. Files have been demultiplexed such that the 5nt degenerate barcode has been appended as the first 5 nucleotides of the read.