MRNA modifications in eukaryotes

After translation modifications of pre-MRNA must take place

The first type of modification is the 5` cap - this involves the addition of a gunaine nucleotide by a very unique 5` to 5` trisophosphate linkage 

The second is the poly A adenylation, also known as the formation of the poly A tail. Terminal part of mRNA is cleaved by endonuclease. A polymerase known as poly(A) polymerase recognises endonuclease, binds and adds around 150-200 adenine nucelotides. These are not encoded in the DNA but are essential in eukaryotes as they increase the stability of the mRNA for exportation and also prevent degradation. 

The final modification is the removal of untranslated regions. Both 5` and 3` untranslated regions in eukaryotic DNA serve a vital role in…