Gene expression is an inherently noisy process capable of displaying phenotypic variation despite constant environmental conditions. This stochastic behavior results from fluctuations in the transcription and translation of genes between identical cells . DNA looping, which is a common means of regulating transcription, is very much a stochastic process; the loops arise from the thermal motion of the DNA and other fluctuations of the cellular environment. We present single-molecule measurements of DNA loop formation and breakdown when an artificial fluctuating force, applied to mimic a fluctuating cellular environment, is imposed on the DNA. We show that loop formation is greatly enhanced in the presence of noise  , yet find that hypothetical regulatory schemes that employ mechanical tension in the DNA--as a sensitive switch to control transcription--can be surprisingly robust due to a fortuitous cancellation of noise effects.
Living cells provide a fluctuating, out-of-equilibrium environment in which genes must coordinate cellular function . DNA looping, which is a common means of regulating transcription, is very much a stochastic process; the loops arise from the thermal motion of the DNA and other fluctuations of the cellular environment. We present single-molecule measurements of DNA loop formation and breakdown when an artificial fluctuating force, applied to mimic a fluctuating cellular environment, is imposed on the DNA. We show that loop formation is greatly enhanced in the presence of noise of only a fraction of k_B T , yet find that hypothetical regulatory schemes that employ mechanical tension in the DNA--as a sensitive switch to control transcription--can be surprisingly robust due to a fortuitous cancellation of noise effects.
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Gene expression is an inherently noisy process capable of displaying phenotypic variation despite constant environmental conditions. This stochastic behavior results from fluctuations in the transcription and translation of genes between identical cells
Living cells provide a fluctuating, out-of-equilibrium environment in which genes must coordinate cellular function
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of only a fraction of k_B T