TheArabidopsis thalianacore splicing factor PORCUPINE/SmE1 requires intron-mediated expression

Abstract

AbstractPlants are prone to genome duplications and tend to preserve multiple gene copies. This is also the case for the genes encoding the Sm proteins ofArabidopsis thaliana(L). The Sm proteins are best known for their roles in RNA processing such as pre-mRNA splicing and nonsense-mediated mRNA decay. In this study, we have taken a closer look at the phylogeny and differential regulation of the SmE-coding genes found inA. thaliana,PCP/SmE1, best known for its cold-sensitive phenotype, and its paralog,PCPL/SmE2. The phylogeny of thePCPhomologs in the green lineage shows thatSmEduplications happened multiple times independently in different plant clades and that the duplication that gave rise toPCPandPCPLoccurred only in the Brassicaceae family. Our analysis revealed thatA. thalianaPCP and PCPL proteins, which only differ in two amino acids, exhibit a very high level of functional conservation and are able to perform the same function in the cell. However, our results indicate thatPCPis the prevailing copy of the twoSmEgenes inA. thalianaas it is more highly expressed and that the main difference betweenPCPandPCPLresides in their transcriptional regulation, which is strongly linked to intronic sequences.