Small RNAs altering antibiotic resistance and their targets in Escherichia coli

Abstract

Noncoding RNA, an RNA that is not encoded by a protein, is involved in various intracellular metabolic processes. Some of them help cells adapt to environmental stress. Noncoding RNAs of E. coli are short, often referred to as small RNAs, and many studies have shown that small RNAs are involved in the process of adapting to environmental stress in E. coli as well. Among the environmental stresses that small RNAs affect, a recent study has shown that small RNAs also affect antibiotic stress. The ongoing use of antibiotics has led to the emergence of several antibiotic-resistant strains, reducing the number of antibiotics that can be used. The World Health Organization and the Centers for Disease Control and continue to investigate the status of antibiotic-resistant bacteria worldwide and classify antibiotic resistance as a major threat to public health. To address the problem of antibiotic resistance, it is important to find out which small RNA of E. coli affects antibiotic resistance and to determine which target gene is responsible for antibiotic resistance.

In this study, we investigated which small RNA changes the antibiotic resistance of E. coli. ArcZ and CyaR seem to be the small RNAs altering antibiotic resistance, were found through different methods. ArcZ small RNA was expected to modulate antibiotic resistance by modulating the expression of the mdtE efflux pump gene. Although regulating the expression of the mdtE gene has been shown in some cases, it has not actually changed the resistance to erythromycin. In contrast, CyaR small RNAs altered resistance to fosfomycin and confirmed that the phenomenon occurred through the yebO gene. The expression of yebO gene was regulated by the presence or absence of CyaR small RNA. CyaR small RNA mutants were constructed and it was confirmed that the 44th nucleotide sequence of CyaR small RNA was important for the expression of yebO gene.