Role of cooperative binding on noise expression

GUTIERREZ, P.S.; MONTEOLIVA, D.; DIAMBRA, L.

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

American Phyical Socienty

Año: 2009 vol. 80 p. 11914 - 11921

1063-651X

The origin of stochastic fluctuations in gene expression has received considerable attention recently. Fluctuationsin gene expression are particularly pronounced in cellular systems because of the small copy numberof species undergoing transitions between discrete chemical states and the small size of biological compartments.In this paper, we propose a stochastic model for gene expression regulation including several bindingsites, considering elementary reactions only. The model is used to investigate the role of cooperativity on theintrinsic fluctuations of gene expression by means of master-equation formalism. We found that the Hillcoefficient and the level of noise increase as the interaction energy between activators increases. Additionally,we show that the model allows one to distinguish between two cooperative binding mechanisms