The function of CPSF4 (cleavage and polyadenylation specific factor 4, Ensembl gene identifier ENSG00000160917) is as follows. Component of the cleavage and polyadenylation specificity factor (CPSF) complex that play a key role in pre-mRNA 3'-end formation, recognizing the AAUAAA signal sequence and interacting with poly(A) polymerase and other factors to bring about cleavage and poly(A) addition. CPSF4 binds RNA polymers with a preference for poly(U). .