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Gal4 vs. LexA systems

S.L. Rennie rennie at bldghsc.lan1.umanitoba.ca
Fri Oct 27 11:39:47 EST 1995


In article <nayers-2610951126170001 at ktraxler.utmem.edu>,
nayers at utmem1.utmem.edu (nancy ayers) wrote:

>  Hello.  I am a graduate student beginning in a study of subunit
> interactions among an oligomeric protein via the two-hybrid system.  We
> have purchased the Clonetech Matchmaker I system and I have already had
> some success with cloning my subunit cDNAs, yet..... All I read here and
> elsewhere indicates that these are not the best vectors, especially for
> confirming by Western blot.  Also, most of the publications I read about
> protein interactions determined by two-hybrid seem to use Brent's LexA
> interaction trap system.  Is this a result of my incomplete literature
> search or is it really the case.  If it is true what are the advantages of
> LexA over Gal4??
> 
> Any comments would be appreciated!!
> Thanks.
> NAncy Ayers
> UT, Memphis
> e-mail: NAYERS at UTMEM1.UTMEM.EDU

-----------------------------------------

General consensus around here is that the lexA promoter has a higher binding
affinity due to the fact that LexA is a complete protein withing the fusion
whereas Gal4 is the partial BD "half" of the protein.  Its also been suggested
that the lexA promoter seq is present in 4 reps? and the gal4 only one or
two(this could be total rumour - I've never looked into this).

Either way we do seem to get better/more consistant/more sensitive?
results using the lexA system

And yes I don't think the strain or vectors sold with the Matchmaker stuff
are the best available....just the only ones "for sale" so far.  For
various reasons people do have trouble confirming expression by Western  

BTW we use a "Stan Fields" version of the 2HS with lexA BD's as well so
there are lots of options

Hope this is the type of info you were looking for
Sharon

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