Transcriptional repression may cause transcriptional noise by a competition between repressor and RNA polymerase binding. Although promoter activity is often governed by a single limiting step, we argue here that the size of the noise strongly depends on whether this step is the initial equilibrium binding or one of the subsequent uni-directional steps. Overall, we show that non-equilibrium steps of transcription initiation systematically increase the cell to cell heterogeneity in bacterial populations. In particular, this allows also weak promoters to give substantial transcriptional noise.
Transcriptional repression may cause transcriptional noise by a competition between repressor and RNA polymerase binding. Although promoter activity is often governed by a single limiting step, we argue here that the size of the noise strongly depends on whether this step is the initial equilibrium binding or one of the subsequent unidirectional steps. Overall, we show that nonequilibrium steps of transcription initiation systematically increase the cell-to-cell heterogeneity in bacterial populations. In particular, this allows also weak promoters to give substantial transcriptional noise.
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uni-directional
unidirectional
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non-equilibrium
nonequilibrium
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cell to cell
cell-to-cell