messengerRNA

Messenger RNA (mRNA) is a type of RNA that carries genetic information copied from DNA in the form of codons, each three nucleotides long, which specify a particular amino acid during protein synthesis. In cells, mRNA serves as the intermediary between transcription and translation. In eukaryotes, mRNA is transcribed by RNA polymerase II from gene templates and then processed before export to the cytoplasm; in prokaryotes transcription and translation are more coupled and mRNAs are typically not processed.

Mature eukaryotic mRNA features include a 5' cap, a 5' to 3' untranslated region (UTR), a coding sequence that dictates protein sequence, a 3' UTR, and a poly(A) tail. RNA splicing removes introns and joins exons; the cap and tail protect mRNA from degradation and assist ribosome recognition. Export from the nucleus to the cytoplasm is mediated by specific transport factors.

During translation, ribosomes read the mRNA's codons to assemble amino acids into a polypeptide chain, using tRNAs as adapters. The mRNA persists only as long as required for protein production and is degraded after its function is fulfilled, through processes such as deadenylation and decapping. mRNA biology is central to gene expression regulation and is a target for research and medical applications, including therapeutic mRNA and vaccines.