This gene encodes a component of the nuclear THO transcription elongation complex, which is part of the larger transcription export (TREX) complex that couples messenger RNA processing and export. In humans, the transcription export complex is recruited to the 5'-end of messenger RNAs in a splicing- and cap-dependent manner. Studies of a related complex in mouse suggest that the metazoan transcription export complex is involved in cell differentiation and development. A pseudogene of this gene has been defined on chromosome 5. [provided by RefSeq, May 2013].