Component of the cleavage and polyadenylation specificity factor (CPSF) complex that plays 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. This subunit is involved in the RNA recognition step of the polyadenylation reaction (By similarity). Plays a role in eye morphogenesis and the development of retinal ganglion cell projections to the tectum (PubMed:30689892). Morpholino knockdown results in abnormal eye morphogenesis, small eye size, and reduced number of retinal ganglion cell projections to the tectum. Belongs to the CPSF1 family.