Heterotypic piRNA Ping-Pong requires qin, a protein with both E3 ligase and Tudor domains.

Zhang Z, Xu J, Koppetsch BS, Wang J, Tipping C, Ma S, Weng Z, Theurkauf WE, Zamore PD
Mol Cell. 2011 Nov 18;44(4):572-84. doi: 10.1016/j.molcel.2011.10.011. (Link opens in a new window) PubMed (Link opens in a new window) Article

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