 Cleavage factor

Cleavage factors are two closely associated protein complexes involved in the cleavage of the 3' untranslated region of a newly synthesized pre-messenger RNA (mRNA) molecule in the process of gene transcription.The cleavage is the first step in adding a polyadenine tail to the pre-mRNA, which is one of the necessary post-transcriptional modifications necessary for producing a mature mRNA molecule.