Cleavage and polyadenylation of the 3' end of pre‑mRNA is a posttranscriptional modification common to most protein‑coding mRNA. It facilitates binding to ribosomes for translation, stabilizes the mRNA molecule, and prevents its degradation by exonucleases. Using recombinant DNA techniques, any gene that has a promoter for RNA polymerase II can instead be connected to a promoter for RNA polymerase I. This hybrid gene is transcribed by RNA polymerase I, but the transcript does not undergo 3' cleavage and polyadenylation. Explain why the hybrid gene mRNA transcript does not undergo 3' cleavage and polyadenylation. Regulatory factors must first associate with RNA polymerase II before 3' cleavage and polyadenylation. Regulatory factors for RNA polymerase I prevent 3' cleavage and polyadenylation. RNA polymerase II binds to the 3' end and prevents processing by RNA polymerase I. Protein‑coding genes have a consensus sequence that interferes with RNA polymerase I and proteins involved in polyadenylation. Recombinant DNA techniques cause premature stop codons that prevent 3'‑end transcription and processing. Question Source: Pierce 6e - Genetics: A Conceptual A