TitleOptimizing information flow in small genetic networks. III. A self-interacting gene.
Publication TypeJournal Article
Year of Publication2012
AuthorsTkačik, G, Walczak, AM, Bialek, W
JournalPhys Rev E Stat Nonlin Soft Matter Phys
Issue4 Pt 1
Date Published2012 Apr
KeywordsAnimals, Computer Simulation, Gene Expression Regulation, Humans, Information Storage and Retrieval, Models, Genetic, Signal Transduction, Transcription Factors

Living cells must control the reading out or "expression" of information encoded in their genomes, and this regulation often is mediated by transcription factors--proteins that bind to DNA and either enhance or repress the expression of nearby genes. But the expression of transcription factor proteins is itself regulated, and many transcription factors regulate their own expression in addition to responding to other input signals. Here we analyze the simplest of such self-regulatory circuits, asking how parameters can be chosen to optimize information transmission from inputs to outputs in the steady state. Some nonzero level of self-regulation is almost always optimal, with self-activation dominant when transcription factor concentrations are low and self-repression dominant when concentrations are high. In steady state the optimal self-activation is never strong enough to induce bistability, although there is a limit in which the optimal parameters are very close to the critical point.

Alternate JournalPhys Rev E Stat Nonlin Soft Matter Phys