| Abstract: |
| The burst of gene expression has been attributed to the random transition between gene active
and inactive states. Our major aim is to understand the regulation of activation process in response to environmental changes. We model the gene activation through the competitive cross-talk between a weak basal pathway and an inducible signaling pathway, and reveal rich expression dynamics and intricate dependence of noise and fano factor on mean expression. An encouraging observation is that those theoretical results are in good agreement with a large set of data in E.\,coli, yeast and mammalian cells. Further theoretical analysis and supporting biological evidences then converge to a trade-off that governs sharp up-and-down regulation of expression, and an ordered scenario that modulates gene activation under varying conditions. These regulation modes, together with cross-talking pathways, may provide new interpretations on experimental observations. |
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