Chicken PPARγ Undergoes Alternative Polyadenylation to Produce Five 3'UTR Isoforms with Distinct Regulatory Functions

Alternative polyadenylation (APA) is a widespread posttranscriptional regulatory process that modulates gene expression. However, its role in regulating peroxisome proliferator-activated receptor γ (PPARγ) remains unknown. Using 3'RACE in chickens, we identified five PPARγ 3'UTR isoforms (S1, S2, M, L1, and L2). RHAPA analysis revealed tissue-specific expression patterns, with both the short (S1, S2, M) and long (L1, L2) isoform pools predominantly expressed in broiler adipose tissue. Reporter assays demonstrated that these isoforms differentially regulated mRNA abundance and translational efficiency, with S2 isoform exhibiting the highest and L2 isoform the lowest reporter activity, independent of mRNA stability. Consistently, the 3'UTR isoforms differentially modulated endogenous PPARγ mRNA and protein levels; however, they did not significantly alter PPARγ transactivation on a PPRE reporter or adipogenic differentiation. Overall, these results provide novel perspectives on the mechanisms regulating PPARγ during adipogenesis and lipid metabolism in poultry.