MicroRNAs recruit eIF4E2 to repress translation of target mRNAs

Abstract

MicroRNAs (miRNAs) recruit the RNA-induced silencing complex (RISC) to repress the translation of target mRNAs. While the 5′ 7-methylguanosine cap of target mRNAs has been well known to be important for miRNA repression, the underlying mechanism is not clear. Here we show that TNRC6A interacts with eIF4E2, a homologue of eIF4E that can bind to the cap but cannot interact with eIF4G to initiate translation, to inhibit the translation of target mRNAs. Downregulation of eIF4E2 relieved miRNA repression of reporter expression. Moreover, eIF4E2 downregulation increased the protein levels of endogenous IMP1, PTEN and PDCD4, whose expression are repressed by endogenous miRNAs. We further provide evidence showing that miRNA enhances eIF4E2 association with the target mRNA. We propose that miRNAs recruit eIF4E2 to compete with eIF4E to repress mRNA translation.

Key words： microRNAs; translation repression; 5′ cap; eIF4E2; TNRC6A

References

1 AsanganiIA, RasheedSA, NikolovaDA, LeupoldJH, ColburnNH, PostS, AllgayerH (2008) MicroRNA-21 (miR-21) post-transcriptionally downregulates tumor suppressor Pdcd4 and stimulates invasion, intravasation and metastasis in colorectal cancer.Oncogene27(15):2128–2136

2 BolandA, TritschlerF, HeimstadtS, IzaurraldeE, WeichenriederO (2010) Crystal structure and ligand binding of the MID domain of a eukaryotic Argonaute protein.Embo Reports11(7):522–527

3 BoyerinasB, ParkSM, ShomronN, HedegaardMM, VintherJ, AndersenJS, FeigC, XuJ, BurgeCB, PeterME (2008) Identification of let-7-regulated oncofetal genes.Cancer Res68 (8):2587–2591

4 ChapatC, JafarnejadSM, Matta-CamachoE, HeskethGG, GelbartIA, AttigJ, GkogkasCG, AlainT, Stern-GinossarN, FabianMR (2017) Cap-binding protein 4EHP effects translation silencing by microRNAs.Proc Natl Acad Sci114:5425–5430

5 ChoPF, PoulinF,Cho-ParkYA, Cho-ParkIB, ChicoineJD, LaskoP, SonenbergN (2005) A new paradigm for translational control: inhibition via 5 ‘-3 ‘ mRNA tethering by Bicoid and the eIF4E cognate 4EHP.Cell121(3):411–423

6 DjuranovicS, ZinchenkoMK, HurJK, NahviA, BrunelleJL, RogersEJ, GreenR (2010) Allosteric regulation of Argonaute proteins by miRNAs.Nat Struct Mol Biol17(2):144–150

7 EulalioA, HuntzingerE, IzaurraldeE (2008) GW182 interaction with Argonaute is essential for miRNA-mediated translational repression and mRNA decay.Nat Struct Mol Biol15(4):346–353

8 FabianMR, SonenbergN, FilipowiczW (2010) Regulation of mRNA translation and stability by microRNAs.Annu Rev Biochem79:351–379

9 FlyntAS, LaiEC (2008) Biological principles of microRNA-mediated regulation: shared themes amid diversity.Nat Rev Genet9 (11):831–842

10 FrankF, FabianMR, StepinskiJ, JemielityJ, DarzynkiewiczE, SonenbergN, NagarB (2011) Structural analysis of 5 ‘-mRNAcap interactions with the human AGO2 MID domain.Embo Reports12(5):415–420

11 FuR, OlsenMT, WebbK, BennettEJ, Lykke-AndersenJ (2016) Recruitment of the 4EHP-GYF2 cap-binding complex to tetraproline motifs of tristetraprolin promotes repression and degradation of mRNAs with AU-rich elements.RNA22(3):373–382

12 FukaoA, MishimaY,TakizawaN, OkaS, ImatakaH, PelletierJ, SonenbergN, ThomaC, FujiwaraT (2014) MicroRNAs trigger dissociation of eIF4AI and eIF4AII from target mRNAs in humans.Mol Cell56(1):79–89

13 FukayaT,TomariY (2012) MicroRNAs mediate gene silencing via multiple different pathways in drosophila.Mol Cell48(6):825–836

14 FukayaT, IwakawaHO, TomariY (2014) MicroRNAs block assembly of eIF4F translation initiation complex in Drosophila.Mol Cell56(1):67–78

15 GingrasAC, RaughtB, SonenbergN (1999) eIF4 initiation factors: effectors of mRNA recruitment to ribosomes and regulators of translation.Annu Rev Biochem68:913–963

16 GuW, XuY, XieX, WangT, KoJH, ZhouT (2014) The role of RNA structure at 5’ untranslated region in microRNA-mediated gene regulation.RNA20(9):1369–1375

17 HeimanM, KulickeR, FensterRJ, GreengardP, HeintzN (2014) Cell type-specific mRNA purification by translating ribosome affinity purification (TRAP).Nat Protoc9(6):1282–1291

18 HumphreysDT, WestmanBJ, MartinDI,PreissT (2005) MicroRNAs control translation initiation by inhibiting eukaryotic initiation factor 4E/cap and poly(A) tail function.Proc Natl Acad Sci U S A102 (47):16961–16966

19 JacksonRJ, HellenCU, PestovaTV (2010) The mechanism of eukaryotic translation initiation and principles of its regulation.Nat Rev Mol Cell Biol11(2):113–127

20 JonasS, IzaurraldeE (2015) NON-CODING RNA Towards a molecular understanding of microRNA-mediated gene silencing.Nat Rev Genet16(7):421–433

21 KamenskaA, LuWT, KubackaD, BroomheadH, MinshallN, BushellM, StandartN (2014) Human 4E-T represses translation of bound mRNAs and enhances microRNA-mediated silencing.Nucleic Acids Res42(5):3298–3313

22 KamenskaA, SimpsonC, VindryC, BroomheadH, BenardM, Ernoult-LangeM, LeeBP,HarriesLW, WeilD, StandartN (2016) The DDX6-4E-T interaction mediates translational repression and P-body assembly.Nucleic Acids Res44(13):6318–6334

23 KinchLN, GrishinNV (2009) The human Ago2 MC region does not contain an eIF4E-like mRNA cap binding motif.Biol Direct4:2

24 KiriakidouM, TanGS, LamprinakiS, De Planell-SaguerM, NelsonPT, MourelatosZ (2007) An mRNA m(7)G cap binding-like motif within human Ago2 represses translation.Cell129 (6):1141–1151

25 KubackaD, KamenskaA, BroomheadH, MinshallN, DarzynkiewiczE, StandartN (2013) Investigating the consequences of eIF4E2 (4EHP) interaction with 4E-transporter on its cellular distribution in HeLa cells.PLoS ONE8(8):e72761

26 LuWT, WilczynskaA, SmithE, BushellM (2014) The diverse roles of the eIF4A family: you are the company you keep.Biochem Soc Trans42:166–172

27 MathonnetG, FabianMR, SvitkinYV, ParsyanA, HuckL, MurataT, BiffoS, MerrickWC, DarzynkiewiczE, PillaiRS (2007) MicroRNA inhibition of translation initiation in vitro by targeting the cap-binding complex eIF4F.Science317(5845):1764–1767

28 MeijerHA, KongYW, LuWT, WilczynskaA, SpriggsRV, RobinsonSW, GodfreyJD, WillisAE, BushellM (2013) Translational repression and eIF4A2 activity are critical for microRNA-mediated gene regulation.Science340(6128):82–85

29 MeisterG (2007) miRNAs get an early start on translational silencing.Cell131(1):25–28

30 MengFY, HensonR, Wehbe-JanekH, GhoshalK, JacobST, PatelT (2007) MicroRNA-21 regulates expression of the PTEN tumor suppressor gene in human hepatocellular cancer.Gastroenterology133(2):647–658

31 NishimuraT, PadamsiZ, FakimH, MiletteS, DunhamWH, GingrasAC, FabianMR (2015) The eIF4E-Binding Protein 4ET Is a Component of the mRNA Decay Machinery that Bridges the 5 ‘ and 3 ‘ Termini of Target mRNAs.Cell Rep11(9):1425–1436

32 PetersenCP, BordeleauME, PelletierJ, SharpPA (2006) Short RNAs repress translation after initiation in mammalian cells.Mol Cell21(4):533–542

33 PfaffJ, MeisterG (2013) Argonaute and GW182 proteins: an effective alliance in gene silencing.Biochem Soc Trans41 (4):855–860

34 PillaiRS, BhattacharyyaSN, ArtusCG, ZollerT, CougotN, BasyukE, BertrandE, FilipowiczW (2005) Inhibition of translational initiation by Let-7 microRNA in human cells.Science309 (5740):1573–1576

35 QiL, BartJ, TanLP, PlatteelI,SluisT, HuitemaS, HarmsG, FuL, HollemaH, BergA (2009) Expression of miR-21 and its targets (PTEN, PDCD4, TM1) in flat epithelial atypia of the breast in relation to ductal carcinoma in situ and invasive carcinoma.BMC Cancer9:163

36 RicciEP, LimousinT, Soto-RifoR, RubilarPS, DecimoD, OhlmannT (2013) miRNA repression of translation in vitro takes place during 43S ribosomal scanning.Nucleic Acids Res41(1):586–598

37 RomE, KimHC, GingrasAC, MarcotrigianoJ, FavreD, OlsenH, BurleySK, SonenbergN (1998) Cloning and characterization of 4EHP, a novel mammalian eIF4E-related cap-binding protein.J Biol Chem273(21):13104–13109

38 SonenbergN, ShatkinAJ (1977) Reovirus messenger-Rna can be covalently crosslinked via 5’ cap to proteins in initiation-complexes.Proc Natl Acad Sci USA74(10):4288–4292

39 TaoX, GaoG (2015) Tristetraprolin Recruits Eukaryotic Initiation Factor 4E2 To Repress Translation of AU-Rich Element-Containing mRNAs.Mol Cell Biol35(22):3921–3932

40 ThermannR, HentzeMW (2007) Drosophila miR2 induces pseudopolysomes and inhibits translation initiation.Nature447 (7146):875–878

41 Valencia-SanchezMA, LiuJ, HannonGJ, ParkerR (2006) Control of translation and mRNA degradation by miRNAs and siRNAs.Genes Dev20(5):515–524

42 VaraniG (1997) A cap for all occasions.Structure5(7):855–858

43 WaltersRW, BradrickSS, GromeierM (2010) Poly(A)-binding protein modulates mRNA susceptibility to cap-dependent miRNA-mediated repression.Rna16(1):239–250

44 WangBB, YanazA, NovinaCD (2008) MicroRNA-repressed mRNAs contain 40S but not 60S components.Proc NatL Acad Sci USA105(14):5343–5348

45 YaoB, LiSQ, JungHM, LianSL,AbadalGX, HanF, FritzlerMJ, ChanEKL (2011) Divergent GW182 functional domains in the regulation of translational silencing.Nucleic Acids Res39(7):2534–2547

46 ZuberekJ, KubackaD, JablonowskaA, JemielityJ, StepinskiJ, SonenbergN, DarzynkiewiczE (2007) Weak binding affinity of human 4EHP for mRNA cap analogs.RNA13(5):691–697