Robo-Therm, a pipeline to RNA thermometer discovery and validation

Abstract

RNA thermometers are highly structured noncoding RNAs located in the 5′-untranslated regions (UTRs) of genes that regulate expression by undergoing conformational changes in response to temperature. The discovery of RNA thermometers through bioinformatics is difficult because there is little sequence conservation among their structural elements. Thus, the abundance of these thermosensitive regulatory structures remains unclear. Herein, to advance the discovery and validation of RNA thermometers, we developed Robo-Therm, a pipeline that combines an adaptive and user-friendly in silico motif search with a well-established reporter system. Through our application of Robo-Therm, we discovered two novel RNA thermometers in bacterial and bacteriophage genomes found in the human gut. One of these thermometers is present in the 5′-UTR of a gene that codes for σ⁷⁰ RNA polymerase subunit in the bacteria Mediterraneibacter gnavus and Bacteroides pectinophilus, and in the bacteriophage Caudoviricetes, which infects B. pectinophilus. The other thermometer is in the 5′-UTR of a tetracycline resistance gene (tetR) in the intestinal bacteria Escherichia coli and Shigella flexneri. Our Robo-Therm pipeline can be applied to discover multiple RNA thermometers across various genomes.