Epistatic interactions between mutations in the transcription factor Rho and RNA polymerase subunit beta in Escherichia coli under thermal stress

In this study, we have constructed eight pairs of rho and rpoB mutations in the same genetic background and compared the fitness of these double mutants against single mutations in the same background. We studied gene expression at high temperature (42.2C) for a subset of the double mutants, measuring gene expression epistasis relative to single mutants and assessing these expression effects in the context of genetic networks. Our overall goals are to gain insights into the properties and potential mechanisms of epistasis in this system.