Impact of G-content on Arabidopsis AtPAB binding and their role in enhancing translational efficiency

Polyadenylation plays a key role in producing mature mRNAs in eukaryotes. It is widely believed that the poly(A)-binding proteins (PABs) uniformly bind to poly(A)-tailed mRNAs, regulating their stability and translational efficiency. Here, we characterized the RNA-binding landscape of three broadly expressed PABs in Arabidopsis thaliana. We observed substantial variation in the AtPAB-binding efficiency among mRNAs, which can be partly explained by the guanosine (G) content of poly(A) tails. AtPAB-binding efficiency of a gene was positively associated with translational efficiency rather than mRNA stability. Consistently, genes with stronger AtPAB binding exhibited a greater reduction in translational efficiency when AtPAB is depleted. Our study provides a new mechanism that translational efficiency of a gene can be regulated through G-content-dependent PAB binding, paving the way for a better understanding of poly(A) tail-associated regulation of gene expression. CLIP-seq and ribosome profiling were used to study direct binding genes and the functions on translational regulation of AtPABs. Poly(A)-seq was used to detect the mRNA tail information in Col. Degradtion data was used to detect mRNA degradation rate in Col.