| 摘要 |
NEW MATERIAL:A plasmid vector giving its host both of tetracycline resisting and ampicillin resisting properties in which has gene giving the ampicillin resistance is partially duplicated and has a site for a restriction enzyme at one end. USE:The plasmid vector permits to utilize the promotor of penicillinase gene, i.e., SD-sequence and signal sequence for expressing the different DNA inserted in Escherichia coli. PREPARATION:The only one EcoRIsite in PBR 322 is eliminated and a new EcoRIsite is introduced into the Hinc II site on the gene giving ampicillin resistance to form a new plasmid vector PMSA 100. Then, PMSA 100 is cleaved at EcoRIand Hind III sites to prepare a DNA fraction containing the gene giving ampicillin resistance. Finally, the resultant DNA fraction is inserted between the EcoRIand the Hind III sites in PBR322 to prepare the objective modified plasmid vector. |
