Protocol Online logo
Top : Forum Archives: : General Lab Techniques

Transformation result - (Sep/04/2006 )

hi, correct sequenced DNA transformed to Rosetta (try to express protein by Rosetta). control DNA got about 100-200 colonies. My two samples got 8 and 3 colonies. I never use Rosetta before and can anybody tell me whether they are ok or not?



What kind of promoter are you using to drive expression of your protein? An inducible promoter? If the DNA and protocol is okay, my guess would be your protein is toxic, and even when the promoter is repressed, low expression levels due to leakiness is sufficient to produce toxicity. It this is true, change to a promoter which has tighter control.

Though, on reflection, 100 colonies for a transformation is very few. How is your DNA (in term of concentration) and are the cells being treated nicely?