Restriction digests of the clone give the following sizes (kb): BamHI--13.6; EcoRI--13.6. Transcription from deoP2 is negatively regulated by the DeoR and CytR repressors and depends on the cAMP/CRP complex. Below 37C, there is one copy per genome equivalent stabilized by the parB locus. At 42C replication is uncontrolled because induction of the cI857-regulated PR promoter permits expression of the copB, copA, and repA genes. Expression of beta-galactosidase from this vector can be increased by the use of hosts containing repressor mutations such as S0929 (cytR), S0930 (deoR) and S0931 (cytR, deoR). Terminator-testing plasmid. Termination signal-containing sequences cloned into the BamHI site may reduce expression of beta-galactosidase activity regulated by the deoP2 promoter. Constructed by inserting a 0.22 kb EcoRI/BamHI fragment containing the deoP2 regulatory region and the first 16 codons of deoC from pJEL134 into pJEL170. |
