Abstract: A system for ligase-free cloning and/or expressing a target gene is described herein. A preferred version of the invention includes an E. coli host. The host preferably includes a T7 RNA polymerase gene comprising a T7gpl coding sequence, a lacUV5 promoter, and a lac operator. The host preferably further includes a lacI gene comprising a lacI coding sequence with an ATG start codon, a promoter derived from the lacql allele, and a translational enhancer derived from a 5? RNA leader sequence of T7 gene 10. The invention further includes a low-copy plasmid vector comprising a T7 promoter a lac operator operationally linked to the T7 promoter. The system is configured to inhibit target gene expression when uninduced and to permit gene expression upon induction by auto-induction.

Abstract: A system for ligase-free cloning and/or expressing a target gene is described herein. A preferred version of the invention includes an E. coli host. The host preferably includes a T7 RNA polymerase gene comprising a T7gpl coding sequence, a lacUV5 promoter, and a lac operator. The host preferably further includes a lacI gene comprising a lacI coding sequence with an ATG start codon, a promoter derived from the lacql allele, and a translational enhancer derived from a 5? RNA leader sequence of T7 gene 10. The invention further includes a low-copy plasmid vector comprising a T7 promoter a lac operator operationally linked to the T7 promoter. The system is configured to inhibit target gene expression when uninduced and to permit gene expression upon induction by auto-induction.