Positive feedback, stochasticity and genetic competence
Positive feedback, stochasticity and genetic competence
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DOI：
10.1088/1478-3975/4/1/004
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发表时间：
2007-03-01
期刊：
影响因子：
2
通讯作者：
Bose, Indrani
中科院分区：
文献类型：
--
作者：
Karmakar, Rajesh;Bose, Indrani
单个基因通过正反馈环调节自己的表达，构成了基因调控网络和信号级联的共同基序。最近关于枯草杆菌细菌群体能力发展的实验表明，自我调节遗传模块本身可以引起两种类型的细胞状态。这些状态对应于主调节器ComK的低和高表达状态。当ComK蛋白水平超过导致自动刺激环完全激活的阈值时，达到高表达状态。基因表达的随机性驱动着这两种稳定状态之间的转换。在这篇文章中，我们在三种可能的情景框架下解释了枯草杆菌细胞群体中双峰蛋白分布的出现。在其中两种情况下，双稳性为二元基因表达提供了基础。在第三种情况下，系统在确定性描述中是单稳的，并且基因表达的随机性单独负责两种表达状态的出现。
A single gene, regulating its own expression via a positive feedback loop, constitutes a common motif in gene regulatory networks and signalling cascades. Recent experiments on the development of competence in the bacterial population B. subtilis show that the autoregulatory genetic module by itself can give rise to two types of cellular states. The states correspond to the low and high expression states of the master regulator ComK. The high expression state is attained when the ComK protein level exceeds a threshold value leading to a full activation of the autostimulatory loop. Stochasticity in gene expression drives the transitions between the two stable states. In this paper, we explain the appearance of bimodal protein distributions in B. subtilis cell population in the framework of three possible scenarios. In two of the cases, bistability provides the basis for binary gene expression. In the third case, the system is monostable in a deterministic description and stochasticity in gene expression is solely responsible for the appearance of the two expression states.