Cleavage and polyadenylation specificity factor subunit 3 (CPSF3)

Component of the cleavage and polyadenylation specificity factor (CPSF) complex that play an integral 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 serves as mRNA 3'-end-processing endonuclease.

Also involved with the histone 3'-end pre-mRNA processing. U7 snRNP- dependent protein which induces both the 3'-endoribonucleolytic cleavage of histone pre-mRNAs and acts as a 5' to 3' exonuclease for degrading the subsequent downstream cleavage product (DCP) of mature histone mRNAs.