Restriction digests of the clone give the following sizes (kb): EcoRI--4.8; BamHI--3.0, 1.8; KpnI--3.4, 1.4. Can be selected with 100 ug/ml ampicillin and/or 75 ug/ml spectinomycin. Permits positive selection because deletion of the aadA fragment is not viable. E. coli JS219 is MC1061 malPp delta534::lacIq. It can be propagated in a lacI+ strain such as C600 in the absence of IPTG, but replication is inefficient. Integration vector permitting positive selection for inserts. Transcription of the replication primer RNA is regulated by the lacZpo promoter/operator. In the presence of lacIq, replication is entirely dependent on the presence of inducer. The repressible replication system permits temporary maintenance of the plasmid, construction of strains with stable integrants of vector derivatives, and recovery of sequences adjacent to cloned fragments. pAM35 (ATCC 77186) differs from pAM34 (ATCC 77185) by deletion of the DraII fragment in pAM34 carrying lacIq. The order of the major features in this plasmid is: lacZpo - ori - rom - transcription terminator - BamHI - MCS - XmaIII - aadA (spcR) - HindIII - MCS - BamHI - transcription terminator - bla. |
