Final answer:
Post-transcriptional regulation involving polyadenylation, splicing, and RNA stability ensures mRNA integrity for protein translation and eliminates mutated mRNAs. Addition of 5' cap and 3'-poly-A tail protects mRNA from degradation, with stability factors in the cytoplasm influencing protein synthesis rates.
Step-by-step explanation:
The process that occurs in the nucleus after polyadenylation and splicing is a crucial aspect of post-transcriptional regulation, which ensures the integrity of the mRNA that will be translated into proteins. This process involves the removal of introns and is aided by spliceosomes, which ligate the exons together. Once the primary transcript, or pre-mRNA, is processed with the addition of a 5' cap and 3'-poly-A tail, not only is the mRNA protected from degradation, but it also signifies its readiness for export to the cytoplasm.
In the cytoplasm, mRNA stability is a critical factor that influences the amount of protein produced. Factors such as microRNAs can decrease mRNA stability, thus promoting mRNA decay and reducing the potential for protein translation. Control of RNA stability is an essential mechanism for maintaining cellular homeostasis and ensuring that aberrant or mutated mRNAs are selectively degraded.