Mature messenger RNA
, often abbreviated as mature mRNA
is a eukaryotic
RNA transcript that has been spliced
and is ready for translation
in the course of protein synthesis
. Unlike the eukaryotic
RNA immediately after transcription
known as precursor messenger RNA
, it consists exclusively of exons
, with all introns
Mature mRNA is also called "mature transcript", "mature RNA" or "mRNA".
The production of a mature mRNA molecule occurs in 3 steps:
- During capping, a 7-methyguanosine residue is attached to the 5'-terminal end of the primary transcripts.
- In polyadenylation , a poly-adenosine tail of about 200 adenylate residues is added by a nuclear polymerase post-transcriptionally.
- RNA splicing removes the non-coding RNA introns leaving behind the coding sequences exons, which are then spliced and joined together to form the final mRNA.