Figure 5From: Conserved generation of short products at piRNA lociModel of Piwi-protein-directed biogenesis of secondary piRNAs and 19 nt fragments. Primary piRNA guides target cleavage and defines the 5' end of the secondary piRNA. 5' part of the target transcript that is not protected by the Piwi protein is trimmed by a 5'-3' exonuclease and the resulting 19-mer is formed.Back to article page