Before revision:  Our analytic results reveal a strong synergistic interaction between positive and negative feedback loops and a critical phase-transition-like phenomenon in the regime of slow promoter switching. Our theory is also applied to study the intrinsic noise structure of stochastic gene expression in coupled gene circuits and a complete decomposition of noise in terms of five different biophysical origins is provided.
After revision:  Our analytic results are further applied to study the intrinsic noise structure of stochastic gene expression in coupled gene circuits and a complete decomposition of noise in terms of five different biophysical origins is provided.