Visions & Reflections What's new in translation initiation? The first translation determines the fate of mRNA

摘要

The two terms 'translation' and 'protein synthesis' are interchangeable in describing the process whereby the genetic code in the form of messenger RNA (mRNA) is deciphered such that amino acids cognate with the triplet code are joined end to end to form a peptide chain. However, new data suggest that the initial act of translation on newly synthesised mRNA also functions to proofread mRNA for errors. Aberrant mRNAs detected in this way are rapidly degraded before their encoded proteins impede normal cell function. Initiation of surveillance translation appears to differ from that of regular protein synthesis in three ways: (i) composition of the substrate; (ii) temporal and spatial restrictions; (iii) factors used to recruit the ribosome. This review discusses translational aspects of mRNA surveillance, primarily in the context of the mammalian system, although much information has come from studies in yeast and other organisms.