This entry is characterised by proteins with alternating conserved and low-complexity regions. Bud13 together with Snu17p and a newly identified factor, Pml1p/Ylr016c, form a novel trimeric complex. called The RES complex, pre-mRNA retention and splicing complex. Subunits of this complex are not essential for viability of yeasts but they are required for efficient splicing in vitro and in vivo. Furthermore, inactivation of this complex causes pre-mRNA leakage from the nucleus. Bud13 contains a unique, phylogenetically conserved C-terminal region of unknown function .
Bud site selection protein 13, also known as pre-mRNA-splicing factor CWC26, belongs to the pre-mRNA retention and splicing (RES) complex. May also be involved in positioning the proximal bud pole signal [PUBMED:8657162, PUBMED:11452010, PUBMED:12871902]. The presence of RES subunit homologues in numerous eukaryotes suggests that its function is evolutionarily conserved [PUBMED:15565172].