THO complex subunit 3 (Thoc3)

Required for efficient export of polyadenylated RNA and spliced mRNA. Acts as part of the THO subcomplex of the TREX complex which is believed to couple mRNA transcription, processing and nuclear export, and which specifically associates with spliced mRNA and not with unspliced pre-mRNA.

TREX is recruited to spliced mRNAs with a transcription-independent mechanism, binds to mRNA upstream of the exon-junction complex (EJC) and can be recruited in a splicing- and cap-dependent way to a region near the 5' end of the mRNA where it functions in mRNA export into the cytoplasm through the TAP/NFX1 pathway (By similarity). .