a question about gene expression in plasmids

P.C. PC at no.email.sorry
Tue Dec 16 09:44:57 EST 2003


The promoter that is normally driving beta-lactamase expression will 
also work fine for your gene (I suppose you need low-level expression). 
You will need a ribosome-binding site (the SD consensus), of course.

Peter

Nick Theodorakis wrote:
> On 15 Dec 2003 08:10:35 -0800, dikla_dar at walla.co.il (diki) wrote:
> 
> 
>>nick_theodorakis at hotmail.com (Nick Theodorakis) wrote in message news:<3fdd17bf.48862163 at netnews.worldnet.att.net>...
>>
>>>On 14 Dec 2003 13:45:21 -0800, dikla_dar at walla.co.il (diki) wrote:
>>>
>>>
>>>>hi everybody!
>>>>my question is: in the plasmid pBR322, 
>>>
>>>Wow! Blast from the past.!
>>>
>>>
>>>>if I replace the whole gene for
>>>>resistance to amp. in a certain insert, is there a good chance that
>>>>the new gene will be expressed as a protein?
>>>
>>>Depends. You got an E coli promoter on that insert?
>>>
>>>
>>>>what are the
>>>>circumstances in which it will happen? thank u very much for
>>>>answering, diki.
>>>
>>>There are a lot better vectors these days to express proteins in coli.
>>>Or is this an exam question?
>>>
>>>
>>>Nick
>>
>>hi! and thank u for answering.
>>yes, u got it wright, this is an exam question...
>>the question doesn't say which insert it is and whar I realy don't
>>understand is what factor determines whether the insert will or will
>>not be expressed.
> 
> 
> The question is not really complete. If you replace "the whole gene"
> for amp resistance, to me that means you deleted the promoter for it
> as well. So your insert should need a promoter active in E coli to be
> expresed, and a Shine-Dalgarno sequence at an appropriate location
> will help as well.
> 
> Nick
> 
> 




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