5ygf

Publication Abstract from PubMed

The Tudor domain-containing (Tdrd) family proteins play a critical role in transposon silencing in animal gonads by recognizing the symmetrically dimethylated arginine (sDMA) on the (G/A)R motif of the N-terminal of PIWI family proteins via the eTud domains. Papi, also known as "Tdrd2," is involved in Zucchini-mediated PIWI-interacting RNA (piRNA) 3'-end maturation. Intriguingly, a recent study showed that, in papi mutant flies, only Piwi-bound piRNAs increased in length, and not Ago3-bound or Aub-bound piRNAs. However, the molecular and structural basis of the Papi-Piwi complex is still not fully understood, which limits mechanistic understanding of the function of Papi in piRNA biogenesis. In the present study, we determined the crystal structures of Papi-eTud in the apo form and in complex with a peptide containing unmethylated or dimethylated R10 residues. Structural and biochemical analysis showed that the Papi interaction region on the Drosophila Piwi contains an RGRRR motif (R7-R11) distinct from the consensus (G/A)R motif recognized by canonical eTud. Mass spectrometry results indicated that Piwi is the major binding partner of Papi in vivo. The papi mutant flies suffered from both fertility and transposon-silencing defects, supporting the important role conferred to Papi in piRNA 3' processing through direct interaction with Piwi proteins.

Structural insights into the sequence-specific recognition of Piwi by Drosophila Papi.,Zhang Y, Liu W, Li R, Gu J, Wu P, Peng C, Ma J, Wu L, Yu Y, Huang Y Proc Natl Acad Sci U S A. 2018 Mar 27;115(13):3374-3379. doi:, 10.1073/pnas.1717116115. Epub 2018 Mar 12. PMID:29531043^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.