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. May function as mRNA 3'-end-processing endonuclease and also be involved in the histone 3'-end pre-mRNA processing. Component of the CPSF complex, at least composed of CPSF160, CPSF100, CPSF73-I, CPSF73-II, CPSF30, FY and FIPS5. Interacts with CPSF30, CPSF100, CPSF160 and FY. Highly expressed in senescence leaves, petals, stamens, pollen and late stages of siliques with seeds. Also detected in roots, stems, leaves and seedlings. The HXHXDH motif is essential for the endoribonuclease activity of the CPSF complex. Embryo lethal. CPSF73-I and CPSF73-II are not functionally redundant, but both are essential in plant development. Belongs to the metallo-beta-lactamase superfamily. RNA-metabolizing metallo-beta-lactamase-like family. INTS11 subfamily.