mRNA

Messenger RNA: a short-lived molecular copy of a gene that tells a cell's protein-making machinery what to build.

• Cells copy genes from DNA into mRNA, which ribosomes read to assemble proteins; mRNA medicines supply a designed message instead.
• Swapping one RNA letter for a modified version (pseudouridine) stops the immune system from destroying it, work honoured by the 2023 Nobel Prize.
• It never enters the nucleus or changes DNA, and is broken down within days, so protein production is temporary.
• Beyond vaccines, personalised cancer vaccines encoding a patient's own tumour mutations are now in late-stage trials.