IPTG is a reagent which mimics the structure of allolactose, and can therefore bind to the lac repressor and prevent it from inhibiting gene expression. Once enough IPTG is added, the T7 gene is normally transcribed and so transcription of the gene of interest downstream of the T7 promoter also begins. [ 6 ]

在需要诱导蛋白表达的时期加入IPTG，IPTG与Lac I结合导致Lac I构象改变，无法与Lac O结合，从而解除对T7 RNA聚合酶基因及目的基因的阻遏，目标基因可以正常转录。

2024年7月26日 · pLysS质粒编码T7噬菌体溶菌酶（lysozyme），该酶能抑制T7 RNA聚合酶活性，在非诱导条件下消除T7启动子转录。 这一特点比BL2（DE3）更适合毒性蛋白的表达。

T7 expression is often very robust but may suffer from undesirable basal (non-induced) transcription especially in DE3 strains. Regulation of IPTG-induced T7 expression is accomplished by co-expressing the lac repressor from a plasmid or a host-encoded lacI gene and by co-expressing T7 lysozyme, the natural inhibitor of T7 RNA polymerase activity.

2013年8月27日 · IPTG是乳糖类似物，可以与阻遏蛋白lacI结合，使其对lacUV5启动子失去阻遏作用，T7 RNA 聚合酶得以合成，继而与pET-28质粒 上的T7启动子结合，启动下游基因包括目的基因的表达，从而产生目的蛋白。

1.对于带普通T7 启动子的质粒，终浓度为0.4mM 的IPTG 可以实现完全诱导，而带有T7lac启动子的载体则需要终浓度为1mM 的IPTG 才能完全诱导。 2.一般的诱导3小时左右就可以收集菌体，如果时间过长可能会使菌体发生自溶，产量减少。

Transform expression plasmid into a T7 strain. Plate out on antibiotic selection plates and incubate overnight at 37°C. Resuspend a single colony in 10 ml liquid culture with antibiotic. Incubate at 37°C until OD reaches 0.4–0.6. Induce with 40 μl of a 100 mM stock of IPTG (final conc. = 0.4 mM) and induce for 2 hours at 37°C.

IPTG induction is a method of regulating protein synthesis by triggering transcription of the lac operon. It requires two key players: During IPTG induction, cells must produce T7 RNA polymerase required for gene transcription; for example, you can use BL21 (DE3) E. coli strain. BL21 (DE3) has the lac gene encoding the lac repressor, LacI.

貌似T7启动子IPTG用0.4mM就能诱导出来，T7lac才需要1mM。 温度一般只会影响它的可溶性吧和产速。 OD600在0.4-1都行的。 至于包涵体跟你的片段长度和你选择的载体有关，融合表达和带有信号肽的载体容易可溶表达. 貌似T7启动子IPTG用0.4mM就能诱导出来，T7lac才需要1mM。 温度一般只会影响它的可溶性吧和产速。 OD600在0.4-1都行的。 至于包涵体跟你的片段长度和你选择的载体有关，融合表达和带有信号肽的载体容易可溶表达. 谢谢，能麻烦你把包涵体形成的 …

3 天之前 · The two most widely employed inducers for T7 expression system, IPTG (Isopropyl ß-D-1-thiogalactopyranoside) and lactose utilized in auto-expression protocols, activate T7 RNA polymerase ...