title: Noise Decomposition Principle in a Coherent Feed-Forward Transcriptional Regulatory Loop.
abstract: Coherent feed-forward loops exist extensively in realistic biological regulatory systems, and are common signaling motifs. Here, we study the characteristics and the propagation mechanism of the output noise in a coherent feed-forward transcriptional regulatory loop that can be divided into a main road and branch. Using the linear noise approximation, we derive analytical formulae for the total noise of the full loop, the noise of the branch, and the noise of the main road, which are verified by the Gillespie algorithm. Importantly, we find that (i) compared with the branch motif or the main road motif, the full motif can effectively attenuate the output noise level; (ii) there is a transition point of system state such that the noise of the main road is dominated when the underlying system is below this point, whereas the noise of the branch is dominated when the system is beyond the point. The entire analysis reveals the mechanism of how the noise is generated and propagated in a simple yet representative signaling module.
authors.affiliation: Department of Physics and Institute of Biophysics, Huazhong Normal UniversityWuhan, China; Department of Physics, College of Science, Huazhong Agricultural UniversityWuhan, China; Institute of Applied Physics, College of Science, Huazhong Agricultural UniversityWuhan, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Gui
authors.affiliation: Department of Physics, College of Science, Huazhong Agricultural University Wuhan, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Physics, College of Science, Huazhong Agricultural University Wuhan, China.
authors.forename: Yuangen
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Physics, College of Science, Huazhong Agricultural University Wuhan, China.
authors.forename: Haiyou
authors.initials: H
authors.lastname: Deng
authors.affiliation: Department of Physics, College of Science, Huazhong Agricultural University Wuhan, China.
authors.forename: Chengzhang
authors.initials: C
authors.lastname: Ma
authors.affiliation: Department of Physics and Institute of Biophysics, Huazhong Normal University Wuhan, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Physics, College of Science, Huazhong Agricultural University Wuhan, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yi
keywords: 87.16.dj; 87.17.Aa; 87.18.Tt; coherent feed-forward loop; expression noise; linear noise approximation; noise decomposition; noise propagation