The Antibiotic Trimethoprim Displays Strong Mutagenic Synergy with 2-Aminopurine

Abstract

We show that trimethoprim (TMP), an antibiotic in current use, displays a strong synergistic effect on mutagenesis in Escherichia coli when paired with the base analog 2-aminopurine (2AP), resulting in a 35-fold increase in mutation frequencies in the rpoB-Rifr system. Combination therapies are often employed both as antibiotic treatments and in cancer chemotherapy. However, mutagenic effects of these combinations are rarely examined. An analysis of the mutational spectra of TMP, 2AP, and their combination indicates that together they trigger a response via an alteration in deoxynucleoside triphosphate (dNTP) ratios that neither compound alone can trigger. A similar, although less strong, response is seen with the frameshift mutagen ICR191 and 2AP. These results underscore the need for testing the effects on mutagenesis of combinations of antibiotics and chemotherapeutics.

Improving Furfural Tolerance of Escherichia coli by Integrating Adaptive Laboratory Evolution with CRISPR-Enabled Trackable Genome Engineering (CREATE)

“…Mutations in rpoB can affect many operons or entire pathways and produce much larger benefits among different mutations. , The rpoB locus previously showed that it can increase the tolerance of E. coli to a variety of antibiotics and organic solvents. − However, few mutations in the rpoB gene were reported to confer furfural tolerance in E. coli .…”

The antiretroviral agents azidothymidine, stavudine, and didanosine have the identical mutational fingerprint in the rpoB region of Escherichia coli

“…Figure 5 allows for a comparison of the data in Figure 4 with the fingerprints of spontaneous mutations, those induced by trimethoprim (TMP), and those occurring in a mutT strain that has a high level of A:T→C:G mutations resulting from oxidative damage to a DNA precursor. Although we have published an earlier version of each of the three spectra shown in Figure 4 (D'Souza et al, 2019; Garibyan et al, 2003), there was concern that in our previous studies we may not have picked the very small colonies, so we redid the spectra of mutT and TMP, making sure to not overlook any initially small colonies (see Section 2). The new spectra of mutT and TMP are shown here (Figure 5).…”

Genetic Diversity for Accelerating Microbial Adaptive Laboratory Evolution

“…There are three main types of chemical agents that are traditionally used to induce mutations, including alkylating compounds, base analogues, and antibiotics, each with different effects. ,, The effect of mutagenic agents is caused by lesions or a modification in the base sequence of the DNA molecule, which leads to a misreading during repair and replication. Alkylating agents mainly modify the bases and phosphoric acid on DNA molecules with alkyl groups.…”

“…Tautomerism occurs in keto and enol forms in pyrimidine molecules, while amino and imino groups are allosteric in purine molecules. Some antibiotics such as trimethoprim can also cause DNA damage or even strand-beaks at a sufficiently high concentration . A successful case of using chemical mutagenesis was reported by Smith and colleagues, who developed an isobutanol-producing strain of Escherichia coli by combining NTG mutagenesis with ALE.…”

“…Some antibiotics such as trimethoprim can also cause DNA damage or even strand-beaks at a sufficiently high concentration. 31 A successful case of using chemical mutagenesis was reported by Smith and colleagues, 29 who developed an isobutanolproducing strain of Escherichia coli by combining NTG mutagenesis with ALE. The parent strain JCL16 was subjected to two rounds of NTG mutagenesis to construct the mutant library, and the NV3 strain with a high substrate-tolerance (8 g/L isobutanol) and high production (21.2 g/L isobutanol) was obtained by the subsequent ALE.…”