(A) A two-part structural motif consisting of a predicted unstructured region (−24 to −18) and a double-stranded region in the poly(A) tail (+8 to +16) correlates with increased isoform stability.
(B) Relationship between half-life, evolutionary conservation and predicted structural character in sequence windows near the poly(A) site. +1 is the first A of the poly(A) tail; −1 is the last nt before the poly(A) tail. Blue bars denote the subset of isoforms with unstructured sequences (≥ 6 predicted unstructured residues) in the indicated sequence window, while red bars denote isoforms in which this sequence is structured (≥ 6 predicted structured residues).