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Cancer Cell Int. 2014 Feb 26;14(1):17. doi: 10.1186/1475-2867-14-17.

An eEF1A1 truncation encoded by PTI-1 exerts its oncogenic effect inside the nucleus.

Cancer cell international

Louise D Dahl, Thomas J Corydon, Liina Ränkel, Karen Margrethe Nielsen, Ernst-Martin Füchtbauer, Charlotte R Knudsen

Affiliations

  1. Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark. [email protected].

PMID: 24571548 PMCID: PMC3941776 DOI: 10.1186/1475-2867-14-17

Abstract

BACKGROUND: The oncogene PTI-1 was originally isolated from a prostate cancer cell line by its capability to transform rat fibroblasts. The PTI-1 mRNA has a very eccentric structure as the 5'UTR is similar to prokaryotic 23S rRNA, while the major open reading frame and the 3'UTR corresponds to a part of the mRNA encoding human translation elongation factor eEF1A1. Thus, the largest open reading frame encodes a truncated version of eEF1A1 lacking the first 67 amino acids, while having three unique N-terminal amino acids. Previously, the UTRs were shown to be a prerequisite for the transforming capacity of the PTI-1 transcript. In this study, we have investigated the possible role of the UTRs in regulating protein expression and localization.

METHODS: The protein expression profiles of a number of PTI-1 mRNA variants were studied in vitro and in vivo. Furthermore, the oncogenic potentials of the same PTI-1 mRNAs were determined by monitoring the capacities of stably transfected cells expressing these mRNAs to induce tumors in nude mice and form foci in cell culture. Finally, the cellular localizations of PTI-1 proteins expressed from these mRNAs were determined by fluorescence microscopy.

RESULTS: The PTI-1 mRNA was found to give rise to multiple protein products that potentially originate from translation initiation at downstream, inframe AUGs within the major open reading frame. At least one of the truncated protein variants was also found to be oncogenic. However, the UTRs did not appear to influence the amount and identities of these truncated protein products. In contrast, our localization studies showed that the UTRs of the transcript promote a nuclear localization of the encoded protein(s).

CONCLUSIONS: Translation of the PTI-1 mRNA results in multiple protein products of which (a) truncated variant(s) may play a predominant role during cellular transformation. The PTI-1 UTRs did not seem to play a role in translation regulation, but appeared to contribute to a nuclear localization of the PTI-1 protein(s). This indicates that the PTI-1 protein(s) exert(s) its/their oncogenic function inside the nucleus.

References

  1. Biochim Biophys Acta. 2005 Feb 14;1727(2):116-24 - PubMed
  2. J Biol Chem. 2005 Oct 28;280(43):36318-25 - PubMed
  3. Proc Natl Acad Sci U S A. 2007 Aug 28;104(35):13930-5 - PubMed
  4. J Biol Chem. 2001 Apr 27;276(17):13593-9 - PubMed
  5. Mol Cell Biochem. 2006 Jun;286(1-2):17-22 - PubMed
  6. J Cell Biol. 1991 Nov;115(4):887-903 - PubMed
  7. Biochem Biophys Res Commun. 2009 Aug 14;386(1):82-8 - PubMed
  8. Anticancer Res. 1992 Mar-Apr;12(2):297-304 - PubMed
  9. Mol Cell. 1999 Jan;3(1):43-54 - PubMed
  10. Eur J Biochem. 2001 Jun;268(12):3407-15 - PubMed
  11. J Biol Chem. 2008 Apr 11;283(15):9606-14 - PubMed
  12. World J Biol Chem. 2010 Dec 26;1(12):362-8 - PubMed
  13. Am J Physiol Renal Physiol. 2009 Dec;297(6):F1518-25 - PubMed
  14. Eur J Biochem. 2003 Aug;270(15):3251-62 - PubMed
  15. Oncogene. 2011 Jan 20;30(3):372-8 - PubMed
  16. Genome Biol. 2002;3(3):REVIEWS0004 - PubMed
  17. Gene. 1996 Sep 26;174(1):19-26 - PubMed
  18. Biochem Biophys Res Commun. 2006 Oct 20;349(2):789-98 - PubMed
  19. Anal Biochem. 1976 May 7;72:248-54 - PubMed
  20. Proc Natl Acad Sci U S A. 1995 Jul 18;92(15):6778-82 - PubMed
  21. FEBS J. 2005 Jan;272(2):413-21 - PubMed
  22. Traffic. 2010 Dec;11(12):1498-505 - PubMed
  23. J Biol Chem. 2003 Oct 10;278(41):40330-6 - PubMed
  24. Int J Biochem Cell Biol. 1999 Jan;31(1):151-62 - PubMed
  25. Cancer Invest. 2008 Oct;26(8):800-8 - PubMed
  26. Mol Cancer. 2009 Aug 03;8:58 - PubMed
  27. Gene. 2001 Oct 3;276(1-2):73-81 - PubMed
  28. J Cell Biol. 1998 Dec 14;143(6):1471-84 - PubMed
  29. Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1764-9 - PubMed
  30. Biosci Biotechnol Biochem. 2002 Jan;66(1):1-21 - PubMed
  31. Tohoku J Exp Med. 2006 Jun;209(2):141-8 - PubMed
  32. J Biol Chem. 2003 Nov 21;278(47):46832-9 - PubMed
  33. Cell Mol Biol (Noisy-le-grand). 1996 Sep;42(6):805-10 - PubMed
  34. Bioessays. 2009 May;31(5):492-5 - PubMed
  35. Ann N Y Acad Sci. 2009 Aug;1171:87-93 - PubMed
  36. Cell Prolif. 2007 Dec;40(6):835-48 - PubMed
  37. Curr Biol. 1999 Mar 25;9(6):333-6 - PubMed
  38. Nucleic Acids Res. 1990 May 11;18(9):2828 - PubMed
  39. Nucleic Acids Res. 1989 Apr 25;17(8):3129-44 - PubMed

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