Final answer:
mRNA stability is influenced by various factors, including 5' caps, poly-A tails, RBPs, and miRNAs. These elements can either stabilize the mRNA or mark it for degradation, affecting the amount of protein synthesized.
Step-by-step explanation:
The stability of mRNA molecules is a key factor in determining how long they last in the cytoplasm and, as a result, how much protein can be synthesized from them. Factors like the length of the poly-A tail, the presence of a 5' cap, and the binding of both RNA-binding proteins (RBPs) and microRNAs (miRNAs) influence mRNA stability. RBPs and miRNAs can bind to the untranslated regions (UTRs) at either end of the mRNA to either stabilize it, allowing for more protein to be made, or mark it for degradation, leading to less protein synthesis.
mRNAs are not inherently stable or unstable; it is the cis elements, such as the UTRs, that contribute to their varied stabilities. miRNAs, in association with the RNA-induced silencing complex (RISC), often result in the rapid decay of the mRNA. In sum, the stability of mRNAs in the cytoplasm is a finely regulated process that impacts protein synthesis significantly.