THO is a multi-protein complex involved in the formation of messenger ribonuclear particles (mRNPs) by coupling transcription with mRNA processing and export. Some studies show that Tho1, like Sub2, can assemble onto the nascent mRNA during transcription and that Tho1 and Sub2 can provide alternative pathways for mRNP biogenesis in the absence of a functional THO complex. This is the C-terminal domain found in Tho1 and MOS11 proteins. The C-terminal region of Tho1 from Saccharomyces cerevisiae, adopts a helical fold similar to that of the WHEP RNA-binding domains of metazoan aminoacyl-tRNA synthetases [1].

1: High-resolution NMR structures of the domains of Saccharomyces cerevisiae Tho1. Jacobsen JO, Allen MD, Freund SM, Bycroft M; Acta Crystallogr F Struct Biol Commun. 2016;72:500-506. PMID:27303905