A ΔdinB mutation that sensitizes Escherichia coli to the lethal effects of UV- and X-radiation.

The DinB (PolIV) protein of Escherichia coli participates in several cellular functions. We investigated a dinB mutation, Δ(dinB-yafN)883(::kan) [referred to as ΔdinB883], which strongly sensitized E. coli cells to both UV- and X-radiation killing.

A molecular characterization of spontaneous frameshift mutagenesis within the trpA gene of Escherichia coli.

Spontaneous frameshift mutations are an important source of genetic variation in all species and cause a large number of genetic disorders in humans. To enhance our understanding of the molecular mechanisms of frameshift mutagenesis, 583 spontaneous Trp+ revertants of two trpA frameshift alleles in Escherichia coli were isolated and DNA sequenced. In order to measure the contribution of methyl-directed mismatch repair to frameshift production, mutational spectra were constructed for both mismatch repair-proficient and repair-defective strains.

Interactions among the Escherichia coli mutT, mutM, and mutY damage prevention pathways.

We have investigated in detail the interactions between the Escherichia coli mutT, mutM, and mutY error-prevention systems. Jointly, these systems protect the cell against the effects of the oxidative stress product, 8-oxoguanine (8-oxoG), a base analog with ambiguous base-pairing properties, pairing with either A or C during DNA synthesis. mutT mutator strains display a specific increase in A.