Thank you for your inquiry. I believe that you are referring to the elements needed in your transcription template to create a functional mRNA. These are located upstream or downstream from your open reading frame (gene). If this is what you are referring to, I have listed the elements below.
Your mRNA transcription template must include:
1. Promoter, preferably the T7 promoter
2. 5′ untranslated region with a strong Kozak sequence
3. ORF beginning with a start codon and ending with a stop codon
4. 3′ untranslated region
5. Poly(A) track top strand (this is not the same as a poly(A) signal)*
6. Unique restriction site at the end of the cassette that is suitable for linearization
*Most plasmids designed for expression in a eukaryotic cell contain a poly(A) signal rather than a poly (A) stretch. If you do not have a poly(A) track in your plasmid a poly(A) tail must be added through a poly(A) polymerase reaction.
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Brea Midthune, Ph.D.
Business Development Analyst II