Temperature Dependence of Leakiness of Transcription Repression Mechanisms of Escherichia coli

摘要

In E. coli, transcription repression is essential in cellular functioning. However, its failure rates are non-negligible. We measured the leakiness rate of lacO3O1 promoter with single RNA sensitivity and its temperature dependence in live cells. After finding strong temperature dependence, we dissected the causes. While RNA polymerase numbers and k_t, the rate of active transcription, vary weakly with temperature, the repression strength (dependent on number of repressors and binding and unbinding rates of repressors to the promoter) is heavily temperature dependent. We conclude that the lacO3O1 leakiness at low temperatures increases as the repression mechanism's efficiency hampers.