DNA sequence analysis of spontaneous histidine mutations in a polA1 strain of Escherichia coli K12 suggests a specific role of the GTGG sequence.

Abstract excerpt

Spontaneously arising histidine mutations in an Escherichia coli K12 strain deficient for DNA polymerase I were analysed at the DNA sequence level. We screened approximately 150,000 colonies and isolated 106 histidine auxotrophs. Of these, 98 were unstable hisC mutations; 12 representative mutants analysed were shown to have arisen by the excision of a single quadruplet repeat in the sequence...

Topics

• Base Sequence
• DNA Polymerase I
• DNA, Bacterial
• Escherichia coli
• Histidine
• Models, Genetic
• Molecular Sequence Data
• Mutation
• Operon
• Repetitive Sequences, Nucleic Acid