A mutation in AAUAAA sequence in eukaryotic mRNA will affect the process by which poly-A tail is added to 3'end of mRNA CCA sequence is present at the 3' end of tRNA which is the site of amino acid attachment CAAT is a consensus sequence present 75 BP upstream to the transcription sta site this is a kind of sequence which help in the initiation of transcription GU...A...AG is a common sequence of all introns, i.e. All the introns sta from GU and ends in AG and mostly in between there will be an A site that is the branch site will be present.