Our analysis has revealed that blanks is required for the generation of small RNAs at convergently transcribed regions . We analyzed the sequencing data obtained from flies with an extra NLS on otherwise wild - type Blanks and found that 666 loci met the cutoff - criterion of a rescue / mutant ratio ≥5 . Overall , there was a very good agreement between the two datasets . Nonetheless , it appears that increased nuclear retention lowers the siRNA yield from more active regions while it may slightly increase the yield from the regions with lower activity ( Supplementary Figure S6A ) . The regions displayed in Figure 7C - E are examples of rather active loci and the traces reflect the reduced yield seen in the rescue with NLS - blanks . It thus appears that in particular the more abundant dsRNA precursors become trapped in the nucleus . The less abundant ones might benefit from the presumably higher nuclear concentration of NLS - Blanks , which may outweigh the negative effect of a prolonged nuclear retention . Importantly , siRNA generation was entirely dependent on the RNA binding capacity of dsRBD2 . When the corresponding data was analyzed , we found that now only 73 loci met the ratio cutoff - criterion and overall the ratios no longer correlated between a rescue with wild - type blanks protein and the rescue with the blanks variant carrying inactivating point mutations in dsRBD2 ( Supplementary Figure S6B ) .