A cooperative stochastic model of gene expression

Recent experiments at the level of a single cell have shown that gene expre ssion occurs in abrupt stochastic bursts. Further, in an ensemble of cells, the levels of proteins produced have a bimodal distribution. In a large fr action of cells, the gene expression is either off or has a high value. We propose a stochastic model of gene expression, the essential features of wh ich are stochasticity and cooperative binding of RNA polymerase. The model can reproduce the bimodal behavior seen in experiments.