Final answer:
After RNA Pol II reaches the cleavage site, poly-A polymerase adds a poly-A tail to the mRNA. In translation, release factors bind to the ribosomal A-site upon encountering a stop codon. Also, snRNPs and transcription factors bind to facilitate splicing and the formation of the transcription initiation complex respectively.
Step-by-step explanation:
After the cleavage site is reached for RNA Pol II, various components are involved in binding to form the functional complexes that drive the processes of transcription and translation. Specifically, at the end of transcription, termination factors or release factors bind depending on the context.
During pre-mRNA processing, after the site is cleaved, an enzyme known as poly-A polymerase binds and adds a poly-A tail to the mRNA. This is important for the stability and export of the mRNA from the nucleus to the cytoplasm. In the context of translation termination, once a stop codon is reached, release factors such as RF1, RF2, and RF3 bind to the A-site of the ribosome. This action facilitates the release of the newly synthesized polypeptide chain and the disassembly of the translation complex.
Moreover, during the splicing of pre-mRNA, small nuclear ribonucleoproteins (snRNPs) bind to form a spliceosome, which is crucial for the removal of introns. Similarly, the recruitment of TFIIA and TFIIB, followed by TFIIE, TFIIF, and TFIIH, forms the transcription initiation complex that enables RNA Pol II to begin synthesizing mRNA.