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发帖数: 13 | 1 IPTG induces the expression of T7 polymerase (T7 pol is under the control of
lac, inducible by IPTG), which in turn translates your gene of interest
because it is under the control of T7 promoter and has to be processed by T7
pol, but not E.coli pol. without IPTG, T7 pol has very low basal expression
level, and your gene of interest will have some low basal expression too.
plysS expresses a low level of lysozyme, which functions as an inhibitor for
T7 pol, and thus, with no IPTG induction, inhib | f*********p
发帖数: 13 | 2 I do not think you fully understood my answer to your question yet. let me put
it this way.
what kind of BL21 are you using? BL21 has BL21 (DE3), (DE3) pLysS, ...
different subtypes. I assume that you are using DE3 related strains. DE3
strain has a lambda phage lysogenized in BL21 e.coli, on which there is a T7
polymerase gene under the control of lac promoter. when you grow the cells up,
no or very little T7 pol can be expressed. when you add IPTG, it induces the
expression of T7 pol, which the |
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