BL21(DE3) and pTrc

Dr. Peter Gegenheimer PGegen at UKans.nolospamare.edu
Fri Feb 11 20:22:26 EST 2000


On Tue, 8 Feb 2000 12:31:26, Petri Kursula <pkursula at cc.oulu.fi> wrote:

ð Confused by all these E.coli genotypes and strains, I would like to know
ð if anyone has used BL21(DE3) cells to produce recombinant proteins from a
ð vector with the trc promoter, such as pTrc99a. If yes, is this expression
ð tightly regulatable by IPTG, or do you get leaky expression?

BL21(DE3) contains the phage T7 RNA polymerase under lac repression; it's used
to express genes cloned behind a T7 promoter. You cannot transform it with a 
plasmid containing the lac repressor; that induces the T7 polymerase gene and 
the cells stop growing. 
 
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