title: Multimodality and flexibility of stochastic gene expression.
abstract: We consider a general class of mathematical models for stochastic gene expression where the transcription rate is allowed to depend on a promoter state variable that can take an arbitrary (finite) number of values. We provide the solution of the master equations in the stationary limit, based on a factorization of the stochastic transition matrix that separates timescales and relative interaction strengths, and we express its entries in terms of parameters that have a natural physical and/or biological interpretation. The solution illustrates the capacity of multiple states promoters to generate multimodal distributions of gene products, without the need for feedback. Furthermore, using the example of a three states promoter operating at low, high, and intermediate expression levels, we show that using multiple states operons will typically lead to a significant reduction of noise in the system. The underlying mechanism is that a three-states promoter can change its level of expression from low to high by passing through an intermediate state with a much smaller increase of fluctuations than by means of a direct transition.
authors.affiliation: Instituto de Matemática e Estatística, Universidade de São Paulo, Rua do Matão, 1010, Cidade Universitária, São Paulo, SP, Brazil, CEP: 05508-090, ginnocentini@gmail.com.
authors.forename: Guilherme da Costa Pereira
authors.initials: Gda C
authors.lastname: Innocentini
authors.forename: Michael
authors.initials: M
authors.lastname: Forger
authors.forename: Alexandre Ferreira
authors.initials: AF
authors.lastname: Ramos
authors.forename: Ovidiu
authors.initials: O
authors.lastname: Radulescu
authors.forename: José Eduardo Martinho
authors.initials: JE
authors.lastname: Hornos
mesh_terms: D019295:Computational Biology; D015870:Gene Expression; D053263:Gene Regulatory Networks; D055641:Mathematical Concepts; D008957:Models, Genetic; D011336:Probability; D011401:Promoter Regions, Genetic; D013269:Stochastic Processes