Preferential initiation at the second AUG of the measles virus F mRNA: a role for the long untranslated region.

In the measles virus fusion (F) mRNA, a 574-bases-long untranslated region (UTR), is followed by three clustered AUGs at codon positions 1 (AUG1), 4 (AUG2), and 15 (AUG3). We established that only translation initiation on AUG1 or AUG2 leads to the synthesis of functional F proteins. In the presence of the UTR translation initiation occurs almost exclusively at AUG2. In its absence, the ribosomes initiate also from AUG1 or AUG3.