 A research by EMBO (Dziembowski, 2004) identified a new complex required for nuclear pre-mRNA retention and splicing.They have purified a novel trimeric complex composed of 3 other subunits (Snu17p, Bud13p and Pml1p) and find that these subunits are not essential for viability but required for efficient splicing (removal of introns) of pre-mRNA.In 2006, "Fleischer et al."