The EJC Binding and Dissociating Activity of PYM Is Regulated in

English version České info

The multi-protein exon junction complex (EJC) is deposited at exon-exon junctions on mRNAs upon splicing. EJCs, with Y14, Mago, eIF4AIII and Barentsz proteins at their core, are landmarks of the nuclear history of RNAs and play important roles in their post-transcriptional regulation. In mammalian cells, the Y14-Mago interacting protein PYM associates with ribosomes and disassembles EJCs in the cytoplasm. However, the physiological function of PYM and its regulation in vivo remains unknown. We have analysed PYM function during Drosophila oogenesis, where the EJC is essential for oskar mRNA localization in the oocyte, a prerequisite for embryonic patterning and germline formation. We find that Drosophila PYM interacts with Y14-Mago but, in contrast to mammalian PYM, does not bind ribosomes. We demonstrate that EJCs associated with oskar mRNA in vivo are disassembled by PYM over-expression in a translation-independent manner, causing oskar mislocalization. Our in vivo analysis shows that the Drosophila PYM C-terminal domain modulates PYM-Y14-Mago interaction, revealing that PYM is regulated in Drosophila. Furthermore, PYM is essential for viability of flies lacking one functional copy of y14 or mago, supporting a role of PYM in EJC homeostasis. Our results highlight a distinct mode of regulation of the EJC-dissociating protein PYM in Drosophila.

Vyšlo v časopise: The EJC Binding and Dissociating Activity of PYM Is Regulated in. PLoS Genet 10(6): e32767. doi:10.1371/journal.pgen.1004455
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pgen.1004455

Souhrn

Zdroje

1. ZhangJ, SunX, QianY, LaDucaJP, MaquatLE (1998) At least one intron is required for the nonsense-mediated decay of triosephosphate isomerase mRNA: a possible link between nuclear splicing and cytoplasmic translation. Mol Cell Biol 18 : 5272–5283.

2. LuS, CullenBR (2003) Analysis of the stimulatory effect of splicing on mRNA production and utilization in mammalian cells. RNA 9 : 618–630.

3. NottA, MeislinSH, MooreMJ (2003) A quantitative analysis of intron effects on mammalian gene expression. RNA 9 : 607–617.

4. HachetO, EphrussiA (2004) Splicing of oskar RNA in the nucleus is coupled to its cytoplasmic localization. Nature 428 : 959–963.

5. MatsumotoK, WassarmanKM, WolffeAP (1998) Nuclear history of a pre-mRNA determines the translational activity of cytoplasmic mRNA. EMBO J 17 : 2107–2121.

6. AlexandrovA, ColognoriD, ShuMD, SteitzJA (2012) Human spliceosomal protein CWC22 plays a role in coupling splicing to exon junction complex deposition and nonsense-mediated decay. Proc Natl Acad Sci U S A 109 : 21313–21318.

7. BarbosaI, HaqueN, FioriniF, BarrandonC, TomasettoC, et al. (2012) Human CWC22 escorts the helicase eIF4AIII to spliceosomes and promotes exon junction complex assembly. Nature Structural & Molecular Biology 19 : 983–U929.

8. SteckelbergAL, BoehmV, GromadzkaAM, GehringNH (2012) CWC22 Connects Pre-mRNA Splicing and Exon Junction Complex Assembly. Cell Reports 2 : 454–461.

9. BonoF, GehringNH (2011) Assembly, disassembly and recycling: the dynamics of exon junction complexes. RNA Biol 8 : 24–29.

10. KuglerJM, LaskoP (2009) Localization, anchoring and translational control of oskar, gurken, bicoid and nanos mRNA during Drosophila oogenesis. Fly (Austin) 3 : 15–28.

11. HachetO, EphrussiA (2001) Drosophila Y14 shuttles to the posterior of the oocyte and is required for oskar mRNA transport. Curr Biol 11 : 1666–1674.

12. MohrSE, DillonST, BoswellRE (2001) The RNA-binding protein Tsunagi interacts with Mago Nashi to establish polarity and localize oskar mRNA during Drosophila oogenesis. Genes Dev 15 : 2886–2899.

13. NewmarkPA, BoswellRE (1994) The mago nashi locus encodes an essential product required for germ plasm assembly in Drosophila. Development 120 : 1303–1313.

14. PalaciosIM, GatfieldD, St JohnstonD, IzaurraldeE (2004) An eIF4AIII-containing complex required for mRNA localization and nonsense-mediated mRNA decay. Nature 427 : 753–757.

15. van EedenFJ, PalaciosIM, PetronczkiM, WestonMJ, St JohnstonD (2001) Barentsz is essential for the posterior localization of oskar mRNA and colocalizes with it to the posterior pole. J Cell Biol 154 : 511–523.

16. ForlerD, KocherT, RodeM, GentzelM, IzaurraldeE, et al. (2003) An efficient protein complex purification method for functional proteomics in higher eukaryotes. Nat Biotechnol 21 : 89–92.

17. BonoF, EbertJ, UnterholznerL, GuttlerT, IzaurraldeE, et al. (2004) Molecular insights into the interaction of PYM with the Mago-Y14 core of the exon junction complex. EMBO Rep 5 : 304–310.

18. GehringNH, LamprinakiS, KulozikAE, HentzeMW (2009) Disassembly of exon junction complexes by PYM. Cell 137 : 536–548.

19. DiemMD, ChanCC, YounisI, DreyfussG (2007) PYM binds the cytoplasmic exon-junction complex and ribosomes to enhance translation of spliced mRNAs. Nat Struct Mol Biol 14 : 1173–1179.

20. OhlsteinB, LavoieCA, VefO, GateffE, McKearinDM (2000) The Drosophila cystoblast differentiation factor, benign gonial cell neoplasm, is related to DExH-box proteins and interacts genetically with bag-of-marbles. Genetics 155 : 1809–1819.

21. GraveleyBR, BrooksAN, CarlsonJW, DuffMO, LandolinJM, et al. (2011) The developmental transcriptome of Drosophila melanogaster. Nature 471 : 473–479.

22. ParkNI, MuenchDG (2007) Biochemical and cellular characterization of the plant ortholog of PYM, a protein that interacts with the exon junction complex core proteins Mago and Y14. Planta 225 : 625–639.

23. NiJQ, ZhouR, CzechB, LiuLP, HolderbaumL, et al. (2011) A genome-scale shRNA resource for transgenic RNAi in Drosophila. Nat Methods 8 : 405–407.

24. BoyneJR, JacksonBR, TaylorA, MacnabSA, WhitehouseA (2010) Kaposi's sarcoma-associated herpesvirus ORF57 protein interacts with PYM to enhance translation of viral intronless mRNAs. EMBO J 29 : 1851–1864.

25. EphrussiA, LehmannR (1992) Induction of germ cell formation by oskar. Nature 358 : 387–392.

26. BonoF, EbertJ, LorentzenE, ContiE (2006) The crystal structure of the exon junction complex reveals how it maintains a stable grip on mRNA. Cell 126 : 713–725.

27. AndersenCB, BallutL, JohansenJS, ChamiehH, NielsenKH, et al. (2006) Structure of the exon junction core complex with a trapped DEAD-box ATPase bound to RNA. Science 313 : 1968–1972.

28. Kim-HaJ, KerrK, MacdonaldPM (1995) Translational regulation of oskar mRNA by bruno, an ovarian RNA-binding protein, is essential. Cell 81 : 403–412.

29. MarkussenFH, MichonAM, BreitwieserW, EphrussiA (1995) Translational control of oskar generates short OSK, the isoform that induces pole plasma assembly. Development 121 : 3723–3732.

30. RongoC, GavisER, LehmannR (1995) Localization of oskar RNA regulates oskar translation and requires Oskar protein. Development 121 : 2737–2746.

31. JennyA, HachetO, ZavorszkyP, CyrklaffA, WestonMD, et al. (2006) A translation-independent role of oskar RNA in early Drosophila oogenesis. Development 133 : 2827–2833.

32. GhoshS, MarchandV, GasparI, EphrussiA (2012) Control of RNP motility and localization by a splicing-dependent structure in oskar mRNA. Nat Struct Mol Biol 19 : 441–449.

33. NewmarkPA, MohrSE, GongL, BoswellRE (1997) mago nashi mediates the posterior follicle cell-to-oocyte signal to organize axis formation in Drosophila. Development 124 : 3197–3207.

34. RoignantJY, TreismanJE (2010) Exon junction complex subunits are required to splice Drosophila MAP kinase, a large heterochromatic gene. Cell 143 : 238–250.