Tejas Functions in piRNA Biogenesis Via Nuage Assembly in Drosophila

In Drosophila, two PIWI family proteins, several Tudor-domain containing (Tdrd) proteins and RNA helicases are assembled at perinuclear region of germline cells, forming nuage to process piRNAs. Among those, Tejas, a fly homolog of mouse Tdrd5, has been known as a robust nuage component required for piRNA biogenesis in germline cells, yet its molecular function remained elusive. To understand further the basis of nuage assembly and function for piRNA biogenesis, we investigated nuage assembly with fluorescent-tagged endogenous proteins including Tejas and monitored the behavior of piRNA precursors and piRNAs. Small RNAs associated with PIWI proteins Aub and Ago3 were Immunoisolated from the tej mutant and heterozygous control Drosophila ovaries.