PROCESS FOR PREPARING PLASMID VECTORS HAVING A HIGH COPY-NUMBER

摘要

Plasmid vectors and a process for the preparation thereof are disclosed having the same replication region as pBR322, but which have a substantially higher copy number per cell. The plasmid vectors contain a G-T point mutation at base pair 3074 of the pBR322 sequence which holds back synthesis of the repressor of plasmid replication, and also contain either no tetracycline resistance gene or the tetracycline resistance gene in an inactivated or weakened state.