title: The role of input noise in transcriptional regulation.
abstract: Gene expression levels fluctuate even under constant external conditions. Much emphasis has usually been placed on the components of this noise that are due to randomness in transcription and translation. Here we focus on the role of noise associated with the inputs to transcriptional regulation; in particular, we analyze the effects of random arrival times and binding of transcription factors to their target sites along the genome. This contribution to the total noise sets a fundamental physical limit to the reliability of genetic control, and has clear signatures, but we show that these are easily obscured by experimental limitations and even by conventional methods for plotting the variance vs. mean expression level. We argue that simple, universal models of noise dominated by transcription and translation are inconsistent with the embedding of gene expression in a network of regulatory interactions. Analysis of recent experiments on transcriptional control in the early Drosophila embryo shows that these results are quantitatively consistent with the predicted signatures of input noise, and we discuss the experiments needed to test the importance of input noise more generally.
authors.affiliation: Joseph Henry Laboratories of Physics, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America. gtkacik@princeton.edu
authors.forename: Gasper
authors.initials: G
authors.lastname: Tkacik
authors.forename: Thomas
authors.initials: T
authors.lastname: Gregor
authors.forename: William
authors.initials: W
authors.lastname: Bialek
mesh_terms: D000465:Algorithms; D000818:Animals; D019295:Computational Biology / Q000379:methods; D004330:Drosophila; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D008954:Models, Biological; D008957:Models, Genetic; D015233:Models, Statistical; D016012:Poisson Distribution; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D014157:Transcription Factors