Before revision:  Here we consider the simplest unit of gene regulation ,  the repressed gene, which is instead characterized by nonlinear dependencies on external parameters , leading to corresponding nonlinear extrinsic noise. We adopt a general methodology to address this nonlinearity based on assuming that the fluctuations exhibit a finite and large correlation time .
After revision:  Here we consider the simplest unit of gene regulation , the repressed gene, which is instead characterized by nonlinear dependencies on external parameters . We then review a general methodology to address this nonlinearity based on assuming that the fluctuations exhibit a finite and large correlation time .