A quantitative model explains single-cell dynamics of the adaptive response in Escherichia coli (Biophysical Journal)

DNA damage caused by alkylating chemicals induces an adaptive response in Escherichia coli that increases the tolerance of cells to further damage. Signalling of the response occurs through irreversible methylation of the Ada protein which acts as a DNA repair protein and damage sensor. Methylated Ada induces its own gene expression through a positive feedback loop. However, random fluctuations in the abundance of Ada jeopardize the reliability of the induction signal. I developed a quantitative model to test how gene expression noise and feedback amplification affect the fidelity of the adaptive response.