Problem: The piRNA pathway utilizes 3 piwi proteins: piwi, Aubergine (Aub), and Argonaute 3 (Ago3). Piwi and Aub typically bind to short antisense piRNAs and together cleave transcripts of TEs. Ago3 typically binds sense piRNAs that are the same as TE transcripts. Why is Ago3 necessary for the piRNA pathway?