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. Has endonuclease activity, and functions as mRNA 3-end-processing endonuclease. Also involved in the histone 3-end pre-mRNA processing. U7 snRNP-dependent protein that 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. Cleavage occurs after the 5-ACCCA-3 sequence in the histone pre-mRNA leaving a 3hydroxyl group on the upstream fragment containing the stem loop (SL) and 5 phosphate on the downstream cleavage product (DCP) starting with CU nucleotides. The U7-dependent 5 to 3 exonuclease activity is processive and degrades the DCP RNA substrate even after complete removal of the U7-binding site. Binds to the downstream cleavage product (DCP) of histone pre-mRNAs and the cleaved DCP RNA substrate in a U7 snRNP dependent manner.Store at -20°C or lower. Aliquot to avoid repeated freezing and thawing. *   http://www.creative-diagnostics.com/Anti-CPSF3-PAb-201193-147.htm