The Arabidopsis thaliana core splicing factor PORCUPINE/SmE1 requires intron-mediated expression

Area of Science:

• Plant molecular biology
• Genomics and gene duplication
• RNA processing

Background:

• Plants frequently undergo genome duplications, retaining multiple gene copies.
• Sm proteins are crucial for RNA processing, including pre-mRNA splicing and nonsense-mediated mRNA decay.

Purpose of the Study:

• Investigate the phylogeny and differential regulation of two Arabidopsis thaliana SmE-coding genes: PCP/SmE1 and its paralog PCPL/SmE2.
• Understand the functional conservation and expression divergence between these paralogous genes.

Main Methods:

• Phylogenetic analysis of SmE homologs in the green lineage.
• Comparative analysis of PCP and PCPL protein sequences.
• Gene expression analysis to determine differential regulation.
• Investigation of the role of intronic sequences in transcriptional regulation.

Main Results:

• SmE gene duplications occurred multiple times independently in plant clades; PCP/PCPL duplication is specific to the Brassicaceae family.
• Arabidopsis PCP and PCPL proteins, differing by only two amino acids, exhibit high functional conservation.
• PCP is the predominant SmE gene in Arabidopsis, showing higher expression than PCPL.
• Transcriptional regulation differences between PCP and PCPL are significantly influenced by intronic sequences.

Conclusions:

• The study elucidates the evolutionary history and functional relationship of SmE paralogs in Arabidopsis.
• Differential transcriptional regulation, particularly involving intronic sequences, contributes to the functional divergence of paralogous genes.
• These findings offer insights into gene expression differentiation as an adaptive mechanism to environmental stress in plants.