Aub and Ago3 Are Recruited to Nuage through Two Mechanisms to Form a Ping-Pong Complex Assembled by Krimper

• Published in: Molecular cell 2015-08, Vol.59 (4), p.564-575
• Main Authors: Webster, Alexandre, Li, Sisi, Hur, Junho K., Wachsmuth, Malte, Bois, Justin S., Perkins, Edward M., Patel, Dinshaw J., Aravin, Alexei A.
• Format: Article
• Language: English
• Subjects: Animals; Argonaute Proteins - metabolism; Cell Line; Cell Nucleus - metabolism; Drosophila melanogaster - cytology; Drosophila melanogaster - genetics; Drosophila melanogaster - metabolism; Drosophila Proteins - chemistry; Drosophila Proteins - metabolism; Drosophila Proteins - physiology; Female; Kinetics; Peptide Initiation Factors - metabolism; Protein Interaction Domains and Motifs; Protein Multimerization; Protein Transport; RNA, Small Interfering - metabolism
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/j.molcel.2015.07.017

In Drosophila, two Piwi proteins, Aubergine (Aub) and Argonaute-3 (Ago3), localize to perinuclear “nuage” granules and use guide piRNAs to target and destroy transposable element transcripts. We find that Aub and Ago3 are recruited to nuage by two different mechanisms. Aub requires a piRNA guide for nuage recruitment, indicating that its localization depends on recognition of RNA targets. Ago3 is recruited to nuage independently of a piRNA cargo and relies on interaction with Krimper, a stable component of nuage that is able to aggregate in the absence of other nuage proteins. We show that Krimper interacts directly with Aub and Ago3 to coordinate the assembly of the ping-pong piRNA processing (4P) complex. Symmetrical dimethylated arginines are required for Aub to interact with Krimper, but they are dispensable for Ago3 to bind Krimper. Our study reveals a multi-step process responsible for the assembly and function of nuage complexes in piRNA-guided transposon repression. [Display omitted] •Aub and Ago3 are recruited to perinuclear nuage compartment by distinct mechanisms•Aub requires association with piRNA for localization to nuage•Krimper, a stable component of nuage, recruits unloaded Ago3 to nuage•Symmetrical dimethylated arginines are required for Aub to interact with Krimper Aub and Ago3 degrade transposon mRNAs in the perinuclear compartment called nuage. Webster et al. show that Aub localization to nuage depends on association with piRNA, whereas Ago3 localization to nuage relies on Krimper, not on piRNA binding.