These diverse size classes, together with our observation that vsRNAs are still present in systems that lack Dicer (Poliovirus infections in dcr−/− MEFs), suggest that the Dicer pathway (which is thought to primarily produce RNAs shorter than 27 nt) may not be the only source for these vsRNAs, and that there may some contribution from baseline levels of PIWI proteins (or other novel proteins) in the various systems. Here, DICER1 is linked to poliovirus infection.