Export factors are Mex67/Tap (large subunit) and Mtr2/p15 (small subunit).

In highest eukaryotes, mRNA export is believed to be splicing-dependent. Splicing recruits the TREX protein complex to spliced messages, serving as an adapter for TAP, a low-affinity RNA-binding protein. However, there are alternative mRNA export pathways that do not rely on splicing for specialized messages such as histones. Recent work also suggest an interplay between splicing-dependent export and one of these alternative mRNA export pathways for secretory and