Noise in Gene Expression Determines Cell Fate in Bacillus subtilis

Random cell-to-cell variations in gene expression within an isogenic population can lead to transitions between alternative states of gene expression. Little is known about how these variations (noise) in natural systems affects such transitions. In Bacillus subtilis, noise in ComK, the protein that regulates competence for DNA uptake, is thought to cause cells to transition to the competent state in which genes encoding DNA uptake proteins are expressed. We demonstrate that noise in comK expression selects cells for competence and that experimental reduction of this noise decreases the number of competent cells. We also show that transitions are limited temporally by a reduction in comK transcription. These results show how such stochastic transitions are regulated in a natural system and suggest that noise characteristics are subject to evolutionary forces.

Source:

Noise in Gene Expression Determines Cell Fate in Bacillus subtilis. Hédia Maamar et al. Science Published Online June 14, 2007.