| Autor: |
Robyn Roberts, Laura K Mayberry, Karen S Browning, Aurélie M Rakotondrafara |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
PLoS ONE, Vol 12, Iss 1, p e0169602 (2017) |
| Druh dokumentu: |
article |
| ISSN: |
1932-6203 |
| DOI: |
10.1371/journal.pone.0169602 |
| Popis: |
We recently identified a remarkably strong (739 nt-long) IRES-like element in the 5' untranslated region (UTR) of Triticum mosaic virus (TriMV, Potyviridae). Here, we define the components of the cap-binding translation initiation complex that are required for TriMV translation. Using bio-layer interferometry and affinity capture of the native translation apparatus, we reveal that the viral translation element has a ten-fold greater affinity for the large subunit eIF4G/eIFiso4G than to the cap binding protein eIF4E/eIFiso4E. This data supports a translation mechanism that is largely dependent on eIF4G and its isoform. The binding of both scaffold isoforms requires an eight base-pair-long hairpin structure located 270 nucleotides upstream of the translation initiation site, which we have previously shown to be crucial for IRES activity. Despite a weak binding affinity to the mRNA, eIFiso4G alone or in combination with eIFiso4E supports TriMV translation in a cap-binding factor-depleted wheat germ extract. Notably, TriMV 5' UTR-mediated translation is dependent upon eIF4A helicase activity, as the addition of the eIF4A inhibitor hippuristanol inhibits 5' UTR-mediated translation. This inhibition is reversible with the addition of recombinant wheat eIF4A. These results and previous observations demonstrate a key role of eIF4G and eIF4A in this unique mechanism of cap-independent-translation. This work provides new insights into the lesser studied translation mechanisms of plant virus-mediated internal translation initiation. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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