An unusual mutation in RepA increases the copy number of a stringently controlled plasmid (Rts1 derivative) by over one hundred fold.
A copy number mutant of the Rts1 replicon (copy number 1-2 copies/cell) was obtained. A one-base substitution in the repA region results in a single amino acid change from histidine to asparagine at position 159. This mutation increased the plasmid copy number by up to 120-fold depending upon the growth conditions. At 42.5 degrees C the plasmid with the wild type replicon was unstable while the mutated replicon was relatively stable.
Yonemitsu
H
H
Department of Microbiology, School of Medicine, University of Pennsylvania, Philadelphia 19104-6076.
Higuchi
H
H
Fujihashi
T
T
Kaji
A
A
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D004265:DNA Helicases; D004252:DNA Mutational Analysis; D004261:DNA Replication / Q000235:genetics*; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics; D005784:Gene Amplification / Q000235:genetics*; D017354:Point Mutation / Q000235:genetics*; D017433:Protein Structure, Secondary; D011506:Proteins; D011815:R Factors / Q000096:biosynthesis*; D012093:Replicon / Q000235:genetics; D013696:Temperature; D015534:Trans-Activators
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D011506:Proteins; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases