Maternal mRNA regulation by the piRNA pathway in the Drosophila embryo, from degradation to stabilization
Event details
| Date | 01.09.2016 |
| Hour | 15:00 › 16:00 |
| Speaker | Jeremy DUFOURT |
| Location | |
| Category | Conferences - Seminars |
Piwi-interacting RNAs (piRNAs) and PIWI proteins play a crucial role in germ cells and germline stem cells, by repressing transposable elements and regulating gene expression. In particular, recent data have demonstrated the implication of the piRNA pathway in post-transcriptional gene regulation in germ cells. In Drosophila, piRNAs produced in the female germline are loaded maternally into the embryo, bound mostly to the PIWI protein Aubergine (Aub). piRNA-loaded Aub is present both in the somatic part of the embryo and at higher levels in the posterior germ plasm, a specialized cytoplasm where germ cells are specified. In the embryo, Aub targets maternal mRNAs through incomplete base-pairing with piRNAs and can induce their destabilization by either direct cleavage or the recruitment the CCR4-NOT deadenylation complex. Aub-dependent unstable mRNAs encode germ cell determinants, which are degraded in the somatic part of the embryo, while they are stabilized and translated in the germ plasm to participate in germ cell development. This raises the question of the role of piRNAs and Aub in the stabilization of these germ cell mRNAs in the germ plasm. Using nanos mRNA that encodes a conserved germline determinant, we show that piRNAs and Aub play an active role in the protection of germ cell mRNAs in the germ plasm. We identify Wispy, the germline-specific non-canonical poly(A) polymerase as directly interacting with Aub and colocalizing with Aub in the germ plasm. We propose that Aub acts by directly recruiting Wispy to germ cell mRNAs, leading to their polyadenylation and stabilization in the germ plasm. These results reveal an unexpected role of piRNAs in mRNA localization and stabilization and identify Aub and piRNAs as key players in orchestrating embryonic patterning through two opposite functions: somatic decay and germline stabilization of germ cell mRNAs.
Practical information
- General public
- Free