T7 expression system Induce lac T7 RNA Gene promoter with polymerase product IPTG lac Gene for operator T7 RNA lac polymerase promoter T7- Cloned promoter gene pET plasmid Chromosome lacl In T7 expression vectors,cloned genes are placed under control of the T7 promoter 2012 Pearson Education,Inc.T7 expression system Induce lac promoter with IPTG T7 RNA polymerase Gene product Chromosome Cloned gene T7 promoter pET plasmid Gene for T7 RNA polymerase lac operator lac promoter lacl © 2012 Pearson Education, Inc. In T7 expression vectors, cloned genes are placed under control of the T7 promoter