UNASSIGNED: We recently identified a remarkably strong (739 nt-long) IRES-like element in the 5' untranslated region (UTR) of @entity67287 (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 @entity5290 /eIFiso4G than to the cap binding protein @entity4043 /eIFiso4E. This data supports a translation mechanism that is largely dependent on @entity5290 and its isoform. The binding of both scaffold isoforms requires an eight base-pair-long hairpin structure located 270 @entity2036 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 @entity3505 germ extract. Notably, TriMV 5' UTR-mediated translation is dependent upon @entity31952 helicase activity, as the addition of the @entity31952 inhibitor @entity69007 inhibits 5' UTR-mediated translation. This inhibition is reversible with the addition of recombinant @entity3505 @entity31952 . These results and previous observations demonstrate a key role of @entity5290 and @entity31952 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.

The @entity67287 5' Leader Binds to Both XXXX and eIFiso4G for Translation.

@entity2036 :: ('MESH:D009711', 'Chemical') :: ['nucleotides'] @entity5290 :: ('1981', 'Gene') :: ['eIF4G'] @entity67287 :: ('431317', 'Species') :: ['Triticum mosaic virus'] @entity31952 :: ('1974', 'Gene') :: ['eIF4A'] @entity3505 :: ('4565', 'Species') :: ['wheat'] @entity4043 :: ('1977', 'Gene') :: ['eIF4E'] @entity69007 :: ('MESH:C510125', 'Chemical') :: ['hippuristanol']
@entity5290 :: (1981,Gene) :: ['eIF4G']
