A role for transcription from a piRNA cluster in de novo piRNA production

De novo production of piRNAs deriving from a GFP transgene. (A) Total RNAs were subjected to Northern blot analysis with internally ³²P-U-radiolabeled antisense or sense GFP probes. (B) Chemical characterization of the 3′ end of GFP-derived antisense piRNAs in #8. Northern blot analysis was performed against total RNAs treated with NaIO₄-mediated oxidation, followed by a β-elimination reaction. let-7, an endogenous miRNA in BmN4 cells, served as a control.