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. Has endonuclease activity and functions as mRNA 3'-end-processing endonuclease. Required for the cotranscriptional processing of 3'-ends of polyadenylated and histone pre-mRNA. Binds 2 Zn(2+) ions per subunit. Component of the cleavage and polyadenylation specificity factor (CPSF) complex, composed of at least Clp, Cpsf73, Cpsf100 and Cpsf160. Interacts with Sym and Cpsf100 forming a core cleavage factor required for both polyadenylated and histone mRNA processing. Interacts with Slbp and Lsm11. Belongs to the metallo-beta-lactamase superfamily. RNA-metabolizing metallo-beta-lactamase-like family. CPSF3 subfamily.