Polyadenylation Signal (PAS): A specific sequence in the mRNA that signals where the poly(A) tail should be added during mRNA processing. 3′ Untranslated Region (3′ UTR): The section of mRNA ...

Grozdanov explained that alternative polyadenylation is an RNA-processing mechanism that determines how an mRNA amino acid sequence ends by selecting specific sites called polyadenylation sites.