title: Effects of promoter leakage on dynamics of gene expression.
abstract: BACKGROUND
  Quantitative analysis of simple molecular networks is an important step forward understanding fundamental intracellular processes. As network motifs occurring recurrently in complex biological networks, gene auto-regulatory circuits have been extensively studied but gene expression dynamics remain to be fully understood, e.g., how promoter leakage affects expression noise is unclear.
  
  
  RESULTS
  In this work, we analyze a gene model with auto regulation, where the promoter is assumed to have one active state with highly efficient transcription and one inactive state with very lowly efficient transcription (termed as promoter leakage). We first derive the analytical distribution of gene product, and then analyze effects of promoter leakage on expression dynamics including bursting kinetics. Interestingly, we find that promoter leakage always reduces expression noise and that increasing the leakage rate tends to simplify phenotypes. In addition, higher leakage results in fewer bursts.
  
  
  CONCLUSIONS
  Our results reveal the essential role of promoter leakage in controlling expression dynamics and further phenotype. Specifically, promoter leakage is a universal mechanism of reducing expression noise, controlling phenotypes in different environments and making the gene produce generate fewer bursts.
authors.affiliation: Guangdong Province Key Laboratory of Computational Science, School of Mathematics and Computational Science, Sun Yat-Sen University, Guangzhou, 510275, PR China. hlfang208@163.com.|Institute of Computational Mathematics, Department of Mathematics, Hunan University of Science and Engineering, Youzhou, 425100, PR China. hlfang208@163.com.
authors.forename: Lifang
authors.initials: L
authors.lastname: Huang
authors.affiliation: Guangdong Province Key Laboratory of Computational Science, School of Mathematics and Computational Science, Sun Yat-Sen University, Guangzhou, 510275, PR China. yzhjiang@mail.sysu.edu.cn.
authors.forename: Zhanjiang
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Guangdong Province Key Laboratory of Computational Science, School of Mathematics and Computational Science, Sun Yat-Sen University, Guangzhou, 510275, PR China. liupeijiangsysu@gmail.com.
authors.forename: Peijiang
authors.initials: P
authors.lastname: Liu
authors.affiliation: Guangdong Province Key Laboratory of Computational Science, School of Mathematics and Computational Science, Sun Yat-Sen University, Guangzhou, 510275, PR China. mcszhtsh@mail.sysu.edu.cn.
authors.forename: Tianshou
authors.initials: T
authors.lastname: Zhou
mesh_terms: D005786:Gene Expression Regulation / Q000235:genetics*; D008957:Models, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics*