The protein encoded by this gene is one subunit of a cleavage factor required for 3' RNA cleavage and polyadenylation processing. The interaction of the protein with the RNA is one of the earliest steps in the assembly of the 3' end processing complex and facilitates the recruitment of other processing factors. This gene encodes the 25kD subunit of the protein complex, which is composed of four polypeptides. [provided by RefSeq, Jul 2008].