Processing of mRNA transcript
In eukaryotes, the mRNA that is released at the end of transcription is called
pre-mRNA.
Pre-mRNA undergoes several changes before it is exported out of the nucleus to
protect it from the cytoplasmic environment.
The 5’ end of the pre-mRNA is capped with a modified form of the G nucleotide.
At the 3’ end, an enzyme in the nucleus adds the poly A tail, a long series of A
nucleotides.