Cloning vector and a process for the preparation thereof

摘要

This invention relates to a method for the preparation of a series of cloning vectors and such cloning vectors prepared therefrom. The method consists in the step of digestion of pRL1 derivative with a restriction enzyme BamHI and digesting the pIJ4026 by BglII and electroeluting the ermE gene. The linear DNA having pRL1 derivative is ligated with ermE gene and then transformed into E. coli GM2163. The transformants are screened for the presence of concatamers and that concatamers of pRL50 and pRL80 DNAs being isolated from E. coli. The transformants are selected under appropriate antibiotic selection pressure.