Fig. 6

NIRVS produce 25–30 nt piRNAs, but not 21-nt siRNAs. Size distribution of small RNAs from published resources mapping to NIRVS in the Ae. aegypti (a) and Ae. albopictus (b) genomes. Black bars represent RNAs that map to the sense strand, gray bars show RNAs that map to the antisense strand. NIRVS-derived piRNAs are biased for sequences that are antisense to viral mRNAs, suggesting potential to target viral RNA. c-d Nucleotide bias at each position of small RNAs mapping to the sense (+) strand (upper panel) and antisense (-) strand (lower panel). NIRVS-derived piRNAs are biased for uridine at position 1 in both Ae. aegypti (c) and Ae. albopictus (d). e Number of all NIRVS-derived piRNAs and secondary NIRVS-derived piRNAs expressed in Ae. aegypti (left charts) and Ae. albopictus (right charts). Ring charts were scaled to reflect normalized piRNA counts of F-NIRVS (red), R-NIRVS (blue), and NIRVS from Reovirus (yellow) (Reovirus-NIRVS have been found only in Ae. aegypti). Numbers reflect piRNAs counts normalized to the corresponding library size. f Left panel, heat map of the relative abundance of NIRVS-derived small RNAs in Aag2 cells in which PIWI expression was silencing using RNAi (dsPiwi4-6, and dsAgo3), compared to control dsRNA treatment. Right panel, heatmap of small RNA enrichment in immunoprecipitations (IP) of the indicated PIWI proteins over control GFP IP. V5 epitope-tagged PIWI transgenes were used for IPs (V5-IP)