Regulation of polyadenylation site choice in plant nuclear mRNA

The polyadenylation machinery plays a critical role in the processing of pre-mRNA into mature mRNA. This process involves a large multiprotein complex that recognizes polyadenylation signals and determines the polyadenylation sites (PASs). The presence of multiple polyadenylation signals within many genes suggests that alternative polyadenylation (APA) mechanism contributes to transcriptome diversity through the production of distinct mRNA isoforms. APA plays a crucial role in plant growth and development, regulates multiple signaling pathways, and modulates responses to various abiotic and biotic stresses. The selection of PASs is regulated by multiple factors, including dysfunction of core polyadenylation machinery components, various stress stimuli, epigenetic modifications, intron splicing, and so on. However, the molecular mechanisms that determine PAS choice in plants are still not fully elucidated. In this review, the classification of PAS switches, biological functions, and regulatory elements of the alterations between two PASs were summarized to explore the underlying mechanisms.