Burger Anat, Walczak Aleksandra M, Wolynes Peter G
Center for Theoretical Biological Physics, University of California San Diego, La Jolla, California, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Oct;86(4 Pt 1):041920. doi: 10.1103/PhysRevE.86.041920. Epub 2012 Oct 31.
Many transcription factors bind to DNA with a remarkable lack of specificity, so that regulatory binding sites compete with an enormous number of nonregulatory "decoy" sites. For an autoregulated gene, we show decoy sites decrease noise in the number of unbound proteins to a Poisson limit that results from binding and unbinding. This noise buffering is optimized for a given protein concentration when decoys have a 1/2 probability of being occupied. Decoys linearly increase the time to approach steady state and exponentially increase the time to switch epigenetically between bistable states.
许多转录因子与DNA结合时特异性极低，以至于调控结合位点会与大量非调控“诱饵”位点相互竞争。对于一个自动调节基因，我们发现诱饵位点可将未结合蛋白数量的噪声降低至由结合和解离导致的泊松极限。当诱饵被占据的概率为1/2时，这种噪声缓冲在给定的蛋白质浓度下达到最优。诱饵会线性增加达到稳态的时间，并指数增加在双稳态之间进行表观遗传转换的时间。
