mRNA is a long, single-stranded polymeric molecule made up of nucleotides that are attached by phosphodiester bonds. Each molecule contains four nitrogenous bases, adenine, guanine, cytosine and uracil.

A mature mRNA molecule consists of 5 regions: coding region, 5′ cap, poly (A) tail 5′ UTR, and 3′ UTR. The coding region is composed of codons, each of which codes for specific amino acids. The 5′ cap is present at the 5′-end and the poly (A) tail is present at the 3′ -end. The UTRs or untranslated regions are present at the 5′ and 3′ regions before and after the coding region, respectively.