Final answer:
The machinery required for cleavage and polyadenylation in mRNA processing includes an endonuclease and poly-A polymerase.
Step-by-step explanation:
The machinery required for both cleavage and polyadenylation includes several enzymes. During cleavage, an endonuclease cuts the pre-mRNA between the AAUAAA consensus sequence and a GU-rich sequence, leaving the AAUAAA sequence on the pre-mRNA. For polyadenylation, an enzyme called poly-A polymerase adds a string of approximately 200 adenine residues to the 3' end, known as the poly-A tail.