Selective overproduction of chloramphenicol acetyltransferase in the T7 expression system

T7 발현체계에서 chloramphenicol acetyltransferase의 선택적 과잉생산

A gene can be selectively overexpressed in E. coli by utilizing the phage T7 RNA polymerase's stringent recognition and active transcription of the T7 promoter. The T7 expression system was constructed such that the T7 RNA polymerase gene is under the control of lacUV5 promoter in one plasmid, and that the target gene, the promoterless chloramphenicol acetyltransferase (CAT) gene with E. coli ribosome binding site is under the control of T7 promoter in the other plasmid. Only the E. coli cells containing both plasmids show high resistance to chloramphenicol. When the copy number of the runaway plasmid containing the polymerase gene was varied by a temperature shift, amounts of the CAT protein synthesized upon induction was correspondingly changed as shown in SDS gel electrophoresis.