ATP-dependent unwinding of messenger RNA structure by eukaryotic initiation factors
- PMID: 3838990
ATP-dependent unwinding of messenger RNA structure by eukaryotic initiation factors
Abstract
Interaction of protein synthesis initiation factors with mRNA has been studied in order to characterize early events in the eukaryotic translation pathway. Individual reovirus mRNAs labeled with 32P in the alpha position relative to the m7G cap and eukaryotic initiation factor (eIF)-4A, -4B, and -4F purified from rabbit reticulocytes were employed. It was found that eIF-4A causes a structural change in mRNA, as evidenced by a nuclease sensitivity test: addition of high concentrations of eIF-4A greatly increase the nuclease sensitivity of the mRNA, suggesting that this factor can melt or "unwind" mRNA structure. ATP is required for this reaction. At low concentrations of eIF-4A, addition of eIF-4B is required for maximal unwinding activity. Thus eIF-4B enhances eIF-4A activity. Addition of eIF-4F also makes the mRNA sensitive to nuclease indicating a similar unwinding role to that of eIF-4A. Stoichiometric comparisons indicate that eIF-4F is more than 20-fold more efficient than eIF-4A in catalyzing this reaction. The unwinding activity of eIF-4F is inhibited by m7GDP, while that of eIF-4A is not. This suggests that eIF-4A functions independent of the 5' cap structure. Our results also suggest that the unwinding activity of eIF-4F is located in the 46,000-dalton polypeptide of this complex, which has shown by others to be similar or identical to eIF-4A.
Similar articles
-
Translation initiation factors that function as RNA helicases from mammals, plants and yeast.Biochim Biophys Acta. 1990 Aug 27;1050(1-3):134-9. doi: 10.1016/0167-4781(90)90154-t. Biochim Biophys Acta. 1990. PMID: 2169888
-
Dominant negative mutants of mammalian translation initiation factor eIF-4A define a critical role for eIF-4F in cap-dependent and cap-independent initiation of translation.EMBO J. 1994 Mar 1;13(5):1205-15. doi: 10.1002/j.1460-2075.1994.tb06370.x. EMBO J. 1994. PMID: 8131750 Free PMC article.
-
The ATP-dependent interaction of eukaryotic initiation factors with mRNA.J Biol Chem. 1987 Mar 15;262(8):3826-32. J Biol Chem. 1987. PMID: 2950099
-
Biochemical evidence supporting a mechanism for cap-independent and internal initiation of eukaryotic mRNA.J Biol Chem. 1988 May 5;263(13):6016-9. J Biol Chem. 1988. PMID: 2966150
-
Targeting translation dependence in cancer.Oncotarget. 2011 Jan-Feb;2(1-2):76-88. doi: 10.18632/oncotarget.218. Oncotarget. 2011. PMID: 21378410 Free PMC article. Review.
Cited by
-
Two related superfamilies of putative helicases involved in replication, recombination, repair and expression of DNA and RNA genomes.Nucleic Acids Res. 1989 Jun 26;17(12):4713-30. doi: 10.1093/nar/17.12.4713. Nucleic Acids Res. 1989. PMID: 2546125 Free PMC article.
-
Modulations of the in vitro translational efficiencies of Yellow Fever virus mRNAs: interactions between coding and noncoding regions.Nucleic Acids Res. 1989 Apr 11;17(7):2463-76. doi: 10.1093/nar/17.7.2463. Nucleic Acids Res. 1989. PMID: 2717400 Free PMC article.
-
Both the 5' untranslated region and the sequences surrounding the start site contribute to efficient initiation of translation in vitro.Mol Cell Biol. 1991 May;11(5):2656-64. doi: 10.1128/mcb.11.5.2656-2664.1991. Mol Cell Biol. 1991. PMID: 2017171 Free PMC article.
-
The splicing factor PRP2, a putative RNA helicase, interacts directly with pre-mRNA.EMBO J. 1994 Feb 15;13(4):888-97. doi: 10.1002/j.1460-2075.1994.tb06332.x. EMBO J. 1994. PMID: 8112302 Free PMC article.
-
Translation initiation of ornithine decarboxylase and nucleocytoplasmic transport of cyclin D1 mRNA are increased in cells overexpressing eukaryotic initiation factor 4E.Proc Natl Acad Sci U S A. 1996 Feb 6;93(3):1065-70. doi: 10.1073/pnas.93.3.1065. Proc Natl Acad Sci U S A. 1996. PMID: 8577715 Free PMC article.
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
Other Literature Sources
Miscellaneous
