I am trying to use a de novo gene synthesis service (Genscript) and one part confuses me:

Where do I pick the choice of promoter? Or is the promoter choice automatic based on my plasmid choice?

e.g. Say I want a regulable promoter (say lac induced by IPTG) how do I specify it? https://www.genscript.com/account/gene_services_gene_synthesis.html

I was given to understand in a related question that with a commercial gene you essentially just "pick the promoter you want"? Or must I somehow manually edit the gene sequence I have to incorporate the promoter I want?

How to put a gene under the control of a regulable promoter?

I can definitely email Genscript in case it is not a part of their default interface but I just wanted to verify my understanding of the matter before I do so.

PS. I even checked out Fischer's GeneArt service & even that interface has nowhere for me to select a specific promoter. Makes me wonder if I am getting the workflow wrong?

Screen-shot of sequence selection from Genscript

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    $\begingroup$ Wouldn't their sales team be able to help out? $\endgroup$
    – James
    Commented Jun 29, 2016 at 5:44
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    $\begingroup$ If I am not mistaken, the promoter should be specified by the cloning plasmid. $\endgroup$
    – March Ho
    Commented Jun 29, 2016 at 7:34
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    $\begingroup$ If you need to add a promoter in an unusual location, you can add it into the synthesized DNA sequence. But normally that's decided by the cloning plasmid. If you put in the right restriction sites you can put your synthesized DNA into any cloning plasmid you want. $\endgroup$
    – user137
    Commented Jun 29, 2016 at 7:43
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    $\begingroup$ Usually you should provide the entire sequence that you want to have (including promoter, polyA sites etc). They will clone this sequence in a plasmid and give it to you. They generally do not check for expression or any other function. That's your job. They just ensure that the sequence provided is correctly synthesized and cloned. $\endgroup$
    Commented Jun 29, 2016 at 9:23
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    $\begingroup$ Just a comment about the PolyA sites, they are not the same as PolyA sequences. If you try to put 20 or more Adenosine in a row they will refuse to synthesize it. Our lab has made plasmids with "120", "240", or "360" adenosine PolyA tails built in, but these are our best estimates because producing these oligos is hard, and sequencing them is almost impossible. $\endgroup$
    – user137
    Commented Jun 29, 2016 at 9:27


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