A polyadenylic acid sequence of variable length (60–200 residues) added post-transcriptionally to the 3′ end of most eukaryotic mRNAs to produce hnRNA, although there are some exceptions (e.g. histone mRNAs). The poly-A tail on mRNA is gradually reduced in length in the cytoplasm. Affinity chromatography with oligo(U) or oligo(dT) is a standard technique for purifying mRNA.
Subjects: Chemistry — Medicine and Health.