Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 2004 Mar 15;378(Pt 3):809–816. doi: 10.1042/BJ20031306

The nuclear tRNA aminoacylation-dependent pathway may be the principal route used to export tRNA from the nucleus in Saccharomyces cerevisiae.

Marta Steiner-Mosonyi 1, Dev Mangroo 1
PMCID: PMC1224000  PMID: 14640976

Abstract

Nuclear tRNA export in Saccharomyces cerevisiae has been proposed to involve three pathways, designated Los1p-dependent, Los1p-independent nuclear aminoacylation-dependent, and Los1p- and nuclear aminoacylation-independent. Here, a comprehensive biochemical analysis was performed to identify tRNAs exported by the aminoacylation-dependent and -independent pathways of S. cerevisiae. Interestingly, the major tRNA species of at least 19 families were found in the aminoacylated form in the nucleus. tRNAs known to be exported by the export receptor Los1p were also aminoacylated in the nucleus of both wild-type and mutant Los1p strains. FISH (fluorescence in situ hybridization) analyses showed that tRNA(Tyr) co-localizes with the U18 small nucleolar RNA in the nucleolus of a tyrosyl-tRNA synthetase mutant strain defective in nuclear tRNA(Tyr) export because of a block in nuclear tRNA(Tyr) aminoacylation. tRNA(Tyr) was also found in the nucleolus of a utp8 mutant strain defective in nuclear tRNA export but not nuclear tRNA aminoacylation. These results strongly suggest that the nuclear aminoacylation-dependent pathway is principally responsible for tRNA export in S. cerevisiae and that Los1p is an export receptor of this pathway. It is also likely that in mammalian cells tRNAs are mainly exported from the nucleus by the nuclear aminoacylation-dependent pathway. In addition, the data are consistent with the idea that nuclear aminoacylation is used as a quality control mechanism for ensuring nuclear export of only mature and functional tRNAs, and that this quality assurance step occurs in the nucleolus.

Full Text

The Full Text of this article is available as a PDF (225.4 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ambrogelly Alexandre, Ahel Ivan, Polycarpo Carla, Bunjun-Srihari Shipra, Krett Bethany, Jacquin-Becker Clarisse, Ruan Benfang, Köhrer Caroline, Stathopoulos Constantinos, RajBhandary Uttam L. Methanocaldococcus jannaschii prolyl-tRNA synthetase charges tRNA(Pro) with cysteine. J Biol Chem. 2002 Jul 18;277(38):34749–34754. doi: 10.1074/jbc.M206929200. [DOI] [PubMed] [Google Scholar]
  2. Arts G. J., Fornerod M., Mattaj I. W. Identification of a nuclear export receptor for tRNA. Curr Biol. 1998 Mar 12;8(6):305–314. doi: 10.1016/s0960-9822(98)70130-7. [DOI] [PubMed] [Google Scholar]
  3. Arts G. J., Kuersten S., Romby P., Ehresmann B., Mattaj I. W. The role of exportin-t in selective nuclear export of mature tRNAs. EMBO J. 1998 Dec 15;17(24):7430–7441. doi: 10.1093/emboj/17.24.7430. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Azad A. K., Stanford D. R., Sarkar S., Hopper A. K. Role of nuclear pools of aminoacyl-tRNA synthetases in tRNA nuclear export. Mol Biol Cell. 2001 May;12(5):1381–1392. doi: 10.1091/mbc.12.5.1381. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bertrand E., Houser-Scott F., Kendall A., Singer R. H., Engelke D. R. Nucleolar localization of early tRNA processing. Genes Dev. 1998 Aug 15;12(16):2463–2468. doi: 10.1101/gad.12.16.2463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Bohnsack Markus T., Regener Kathrin, Schwappach Blanche, Saffrich Rainer, Paraskeva Efrosyni, Hartmann Enno, Görlich Dirk. Exp5 exports eEF1A via tRNA from nuclei and synergizes with other transport pathways to confine translation to the cytoplasm. EMBO J. 2002 Nov 15;21(22):6205–6215. doi: 10.1093/emboj/cdf613. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Calado Angelo, Treichel Nathalie, Müller Eva-Christina, Otto Albrecht, Kutay Ulrike. Exportin-5-mediated nuclear export of eukaryotic elongation factor 1A and tRNA. EMBO J. 2002 Nov 15;21(22):6216–6224. doi: 10.1093/emboj/cdf620. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Cleary J. D., Mangroo D. Nucleotides of the tRNA D-stem that play an important role in nuclear-tRNA export in Saccharomyces cerevisiae. Biochem J. 2000 Apr 1;347(Pt 1):115–122. [PMC free article] [PubMed] [Google Scholar]
  9. Feng Wenqin, Hopper Anita K. A Los1p-independent pathway for nuclear export of intronless tRNAs in Saccharomycescerevisiae. Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):5412–5417. doi: 10.1073/pnas.082682699. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Grosshans H., Hurt E., Simos G. An aminoacylation-dependent nuclear tRNA export pathway in yeast. Genes Dev. 2000 Apr 1;14(7):830–840. [PMC free article] [PubMed] [Google Scholar]
  11. Hellmuth K., Lau D. M., Bischoff F. R., Künzler M., Hurt E., Simos G. Yeast Los1p has properties of an exportin-like nucleocytoplasmic transport factor for tRNA. Mol Cell Biol. 1998 Nov;18(11):6374–6386. doi: 10.1128/mcb.18.11.6374. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hopper Anita K., Phizicky Eric M. tRNA transfers to the limelight. Genes Dev. 2003 Jan 15;17(2):162–180. doi: 10.1101/gad.1049103. [DOI] [PubMed] [Google Scholar]
  13. Hurt D. J., Wang S. S., Lin Y. H., Hopper A. K. Cloning and characterization of LOS1, a Saccharomyces cerevisiae gene that affects tRNA splicing. Mol Cell Biol. 1987 Mar;7(3):1208–1216. doi: 10.1128/mcb.7.3.1208. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Ko Y. G., Kang Y. S., Kim E. K., Park S. G., Kim S. Nucleolar localization of human methionyl-tRNA synthetase and its role in ribosomal RNA synthesis. J Cell Biol. 2000 May 1;149(3):567–574. doi: 10.1083/jcb.149.3.567. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Kutay U., Lipowsky G., Izaurralde E., Bischoff F. R., Schwarzmaier P., Hartmann E., Görlich D. Identification of a tRNA-specific nuclear export receptor. Mol Cell. 1998 Feb;1(3):359–369. doi: 10.1016/s1097-2765(00)80036-2. [DOI] [PubMed] [Google Scholar]
  16. Lipowsky G., Bischoff F. R., Izaurralde E., Kutay U., Schäfer S., Gross H. J., Beier H., Görlich D. Coordination of tRNA nuclear export with processing of tRNA. RNA. 1999 Apr;5(4):539–549. doi: 10.1017/s1355838299982134. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Lund E., Dahlberg J. E. Proofreading and aminoacylation of tRNAs before export from the nucleus. Science. 1998 Dec 11;282(5396):2082–2085. doi: 10.1126/science.282.5396.2082. [DOI] [PubMed] [Google Scholar]
  18. Mangroo D., RajBhandary U. L. Mutants of Escherichia coli initiator tRNA defective in initiation. Effects of overproduction of methionyl-tRNA transformylase and the initiation factors IF2 and IF3. J Biol Chem. 1995 May 19;270(20):12203–12209. doi: 10.1074/jbc.270.20.12203. [DOI] [PubMed] [Google Scholar]
  19. Sarkar S., Azad A. K., Hopper A. K. Nuclear tRNA aminoacylation and its role in nuclear export of endogenous tRNAs in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A. 1999 Dec 7;96(25):14366–14371. doi: 10.1073/pnas.96.25.14366. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Sarkar S., Hopper A. K. tRNA nuclear export in saccharomyces cerevisiae: in situ hybridization analysis. Mol Biol Cell. 1998 Nov;9(11):3041–3055. doi: 10.1091/mbc.9.11.3041. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Sharma K., Fabre E., Tekotte H., Hurt E. C., Tollervey D. Yeast nucleoporin mutants are defective in pre-tRNA splicing. Mol Cell Biol. 1996 Jan;16(1):294–301. doi: 10.1128/mcb.16.1.294. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Shen W. C., Selvakumar D., Stanford D. R., Hopper A. K. The Saccharomyces cerevisiae LOS1 gene involved in pre-tRNA splicing encodes a nuclear protein that behaves as a component of the nuclear matrix. J Biol Chem. 1993 Sep 15;268(26):19436–19444. [PubMed] [Google Scholar]
  23. Simos G., Tekotte H., Grosjean H., Segref A., Sharma K., Tollervey D., Hurt E. C. Nuclear pore proteins are involved in the biogenesis of functional tRNA. EMBO J. 1996 May 1;15(9):2270–2284. [PMC free article] [PubMed] [Google Scholar]
  24. Steiner-Mosonyi Marta, Leslie Deena M., Dehghani Hesam, Aitchison John D., Mangroo Dev. Utp8p is an essential intranuclear component of the nuclear tRNA export machinery of Saccharomyces cerevisiae. J Biol Chem. 2003 Jun 6;278(34):32236–32245. doi: 10.1074/jbc.M302779200. [DOI] [PubMed] [Google Scholar]
  25. Tschochner Herbert, Hurt Ed. Pre-ribosomes on the road from the nucleolus to the cytoplasm. Trends Cell Biol. 2003 May;13(5):255–263. doi: 10.1016/s0962-8924(03)00054-0. [DOI] [PubMed] [Google Scholar]
  26. Varshney U., Lee C. P., RajBhandary U. L. Direct analysis of aminoacylation levels of tRNAs in vivo. Application to studying recognition of Escherichia coli initiator tRNA mutants by glutaminyl-tRNA synthetase. J Biol Chem. 1991 Dec 25;266(36):24712–24718. [PubMed] [Google Scholar]
  27. Wise J. A. Preparation and analysis of low molecular weight RNAs and small ribonucleoproteins. Methods Enzymol. 1991;194:405–415. doi: 10.1016/0076-6879(91)94031-7. [DOI] [PubMed] [Google Scholar]
  28. Yoshihisa Tohru, Yunoki-Esaki Kaori, Ohshima Chie, Tanaka Nobuyuki, Endo Toshiya. Possibility of cytoplasmic pre-tRNA splicing: the yeast tRNA splicing endonuclease mainly localizes on the mitochondria. Mol Biol Cell. 2003 May 3;14(8):3266–3279. doi: 10.1091/mbc.E02-11-0757. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES