What determines the amount of protein made from an mRNA?

The protein yield from each mRNA molecule depends on the effectiveness of translation, initiation, and elongation along the coding sequence (CDS), as well as the mRNA's functional half-life. These factors are influenced by features encoded in the primary mRNA sequence. The choice of which codons to use in a gene's sequence directly affects how efficiently the gene is translated into a protein. Genes that are highly expressed tend to use codons that the cell's translation system can interpret more easily. Conversely, using less optimal codons can slow down translation and even reduce the stability of the mRNA molecule itself. Additionally, the frequency of certain pairs of nucleotides within the coding region, and the order in which codons appear can also influence protein production. For instance, the sequence of codons can impact how readily the cell's transfer RNA molecules are matched to the codons during translation. Translational efficiency is also influenced by ribosome occupancy; higher ribosome occupancy generally leads to more efficient translation and higher protein output.