Regulation of dihydrofolate reductase synthesis in Escherichia coli.

摘要: Two clones from the Clarke-Carbon Escherichia coli colony bank were resistant to inhibition by trimethoprim, a potent inhibitor of dihydrofolate reductase. Both had elevated levels Furthermore, trimethoprim resistance and enzyme associated with ColE1 plasmids that carried DNA trkC ksgA pdxA region E. chromosome. Plasmid pLC1437a was shown two criteria carry structural gene for reductase: 1) A partial diploid containing plasmid produced kinetically-recognizable reductase not present in parent haploid strain. 2) coded vitro. 1,000 base pair fragment fol used as probe measure mRNA mutant strain isolated Sheldon Brenner (Molec. gen. Genet. 147, 91–97, 1976). The mutation this strain, which results constitutively-high inability grow at 42° C, is cis dominant (Sheldon Brenner, kinetic hybridization pulse-labeling experiments indicated regulatory response an increased rate synthesis mRNA.