A System for the Rapid Determination of the Mutation Spectrum in Escherichia coli

Abstract

The first step toward elucidating the mutagenic effects of chemicals and pathways is to determine the specificity of the mutations generated spontaneously or in response to treatment with mutagens. We constructed a set of plasmid-encoded probes for the specific detection of each type of base substitution mutation. Using these probes, we were able to quickly determine both the mutation rate and the specificity of the mutations caused by different types of mutagens and mutagenic conditions. We also developed a PCR-based method to rapidly and robustly determine the mutation spectrum in response to various mutagenic samples in parallel. This system allows one to not only analyze the mutation specificity of various chemicals, but also to search for novel genetic elements that promote the specific mutation events.

Transcription Factors as Evolvable Biosensors

“…This system is unique, particularly in the selection mechanism for off-state selection. Instead of using biochemically toxic genes, such as metal sensitizers 29 or degradation enzymes, we adopted an artificial nucleoside called dP that could be highly mutagenic only when phosphorylated 32,33 (Fig. 2).…”