Cleavage factor Im (CFIm) is one of six factors necessary for correct cleavage and polyadenylation of pre-mRNAs. CFIm is composed of three different subunits of 25, 59, and 68 kDa, and it functions as a heterotetramer, with a dimer of the 25 kDa subunit binding to two of the 59 or 68 kDa subunits. The protein encoded by this gene represents the 59 kDa subunit, which can interact with the splicing factor U2 snRNP Auxiliary Factor (U2AF) 65 to link the splicing and polyadenylation complexes.