Design of expression plasmids using tools from custom vector suppliers

Do you need an expression plasmid that is not commercially available (e.g. a mutated variant)?

Whether you want the plasmid to contain a mutated gene or a wild-type coding sequence, here is a quick step-by-step guide.

First: Find the sequence

The first thing is to find the coding sequence of the wild gene that expresses the protein you want. To do this, go to https://www.ncbi.nlm.nih.gov/ and search the name of your interest gene using the Nucleotide search.

Then click on the desired organism and select mRNA. Choose the best entry for your query according to your requirement, and select the CDS (and the protein sequence will appear on the right, a.k.a., translation). 

Next, copy-paste both FASTA text codes into a Word file. We will need them later.

Graphic representation of a DNA molecule.

Second: If you only want to express the wild-type protein...

Paste the CDS directly into the corresponding ORF item from the supplier (e.g. VectorBuilder). 

Example involving a plasmid construction provider.

You will then only need to choose the promoter (usually a CMV) and a tag (fluorescent or not) that can be detected indirectly.

Second: If you want to express the mutant or synthetic protein?

Click on your "/db_xref="CCDS:" to know the corresponding sequence(s) of the CDS to the amino acid(s) you want to change/remove (another web page will be opened, there, when you click on an amino acid, the corresponding genetic codon is marked in the nucleotide sequence).

Edit the sequence(s) in the Word file.

Use the genetic code to choose the codon whose nucleic bases translate your new amino acid(s).

Genetic code that translates RNA nucleotide codons into amino acids.

Then, paste its CDS directly into the corresponding ORF gap of the website from the supplier.

Sources

Section 'If you only want to express the wild-type protein...':

• Mammalian Gene Expression Vector Design Studio | VectorBuilder. (n.d.). Retrieved October 30, 2026, from https://en.vectorbuilder.com/design/pRP_Exp.html

Section 'Do you want to express a mutant or synthetic protein?':

• Genetic Code. (n.d.). Retrieved October 30, 2026, from https://www.genome.gov/genetics-glossary/Genetic-Code

Jaime D.L.A.