Arabidopsis SME interactome reveals spliceosome components

Alternative splicing (AS) can produce multiple transcripts with different exon-intron structures from a single pre-mRNA. Pre-mRNA splicing is catalyzed by a dynamic macromolecular ribonucleoprotein (RNP) complex termed the spliceosome. The spliceosome consists of several small nuclear ribonucleoproteins (snRNPs) that bind uridine-rich small nuclear RNA (snRNA). In U1, U2, U4 and U5 snRNPs, snRNA interacts with the conserved Smith antigen (Sm) proteins via a bipartite Sm sequence motif. In eukaryotes, seven Sm proteins (B, D1/2/3, E, F and G) form a heptameric ring-shaped complex surrounding the snRNA. Here, we performed a tandem affinity purification using SMEB as a bait in Arabidopsis cell suspension cultures. At least 45 known/hypothesized and potential novel spliceosome components were identified in Arabidopsis.