Fig. 3

RNA immunoprecipitation sequencing of PIWI proteins and detection of 3′-2′-O-methylation in oocyte small RNAs. A Expression of piRNA pathway-related genes in oocytes from the 12 representative vertebrate species. Hierarchical clustering was used for to generate a heatmap (method = ‘complete’). Black indicates that a species did not have the corresponding gene in its genome. B–D PIWIL1 and PIWIL3 RNA immunoprecipitation analysis in oocytes from guinea pig (B), pig (C), and goat (D). IgG IP was used as the negative control. The Y-axis scale compares the amount of small RNAs between PIWIL immunoprecipitation and IgG controls within species. E PIWIL1 RNA immunoprecipitation analysis in rat oocytes. IgG IP was used as the negative control. Y-axis scale compares the amount of small RNAs between PIWIL immunoprecipitation and the IgG control within species. F Small RNA composition in oocyte samples treated with NaIO4 (oxidation) or in untreated samples (control). GP, guinea pig; GH, golden hamster; CH, Chinese hamster. Y-axis scales are used for within-species comparisons of small RNA levels with or without NaIO4 treatment