Positional requirements for the stimulation of mRNA nuclear export by ALREX-promoting elements

The majority of vertebrate mRNAs that encode secreted, membrane-bound or mitochondrial proteins contain elements at the 5' end of the ORF that activate an alternative mRNA nuclear export (ALREX) pathway. Here we demonstrate that these elements promote efficient export and proper cytoplasmic localization only when they are found at the 5' end of the transcript.