Functional characterization of PRP43a, a component for splicing disassembly in Arabidopsis

Pre-mRNA splicing is a crucial regulatory process in eukaryotes, ensuring accurate mRNA maturation and contributing to transcript diversity through alternative splicing (AS). This process is mediated by the spliceosome, a large molecular complex composed of small nuclear RNAs (snRNAs) and proteins. Structural and comparative analysis have showed that splicing factors are highly conserved across eukaryotes, though the extent of their functional conservation remains to be fully elucidated. In Arabidopsis, two homologous genes, PRP43a and PRP43b, encode components involved in spliceosome disassembly. To investigate the roles of these genes, we characterized T-DNA insertion mutants prp43a-1 and prp43b-1. While prp43b-1 homozygous mutants were embryonic lethal, prp43a-1 mutants displayed no significant developmental defects under normal conditions, nor did they exhibit impaired heat tolerance. However, RNA-seq analysis revealed transcriptional changes in prp43a-1 under normal conditions. Gene ontology (GO) analysis indicated and enrichment of stress-related processes among the differentially expressed genes (DEGs), suggesting a role for PRP43a in stress responses. Additionally, differential alternative splicing (DAS) analysis identified numerous PRP43a-dependent intron retention (IR) events, particularly under heat stress, indicating that PRP43a influences AS under environmental conditions. These findings suggest PRP43a as a modulator of splicing and gene expression, with potential roles in stress responses. Examinination of mRNA expression patterns in Arabidopsis prp43a-1 mutant