Second-site revertants of the P1 copN22 copy mutant.
Miniplasmids with the P1 copN22 mutation have a copy number about seven times that of the wild type. Selection for reduced copy number from this plasmid led to the isolation of second-site pseudorevertants, called poc mutants. DNA sequence analysis showed that all six independent poc mutants have a single base change in the same codon of the repA gene. This implicates the amino acid at this location, either directly or indirectly, in interactions important for copy number control.
Department of Microbiology and Immunology, Emory University Health Sciences Center, Atlanta, Georgia 30322.
B J
BJ
Froehlich
J R
JR
Scott
D001483:Base Sequence; D003062:Codon / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D015183:Restriction Mapping
D003062:Codon; D004269:DNA, Bacterial