Measurement of the Copy Number of the Master Quorum-Sensing Regulator of a Bacterial Cell
Measurement of the Copy Number of the Master Quorum-Sensing Regulator of a Bacterial Cell
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DOI：
10.1016/j.bpj.2010.01.031
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发表时间：
2010-05-05
影响因子：
3.4
通讯作者：
Ong, N. P.
中科院分区：
文献类型：
--
作者：
Teng, Shu-Wen;Wang, Yufang;Ong, N. P.
群体感应是细菌交流和同步群体行为的机制。诸如特定群体感应蛋白的拷贝数等参数的定量信息将有助于理解群体感应网络的功能。在这里，我们证明了通过利用细胞分裂时蛋白质分布的少量波动，可以在体内确定哈维弧菌的主调节蛋白LuxR的拷贝数。当细胞分裂时，其体积和LuxR蛋白拷贝数N都有轻微的不对称分割。我们测量了描述蛋白质荧光和细胞体积分配的分布函数。发现荧光分布随着LuxR种群的增加而系统地缩小，而体积分配不变。对这些变化进行统计分析，我们确定低细胞密度时N = 80-135二聚体，高细胞密度时N = 575二聚体。此外，我们测量了LuxR在一个大型（3000）克隆群体中的静态分布。结合静态和延时实验，我们确定了分布的Fano因子的大小。该技术作为测定蛋白质拷贝数和爆发大小的一般体内技术具有广泛的适用性。
Quorum-sensing is the mechanism by which bacteria communicate and synchronize group behaviors. Quantitative information on parameters such as the copy number of particular quorum-sensing proteins should contribute strongly to understanding how the quorum-sensing network functions. Here, we show that the copy number of the master regulator protein LuxR in Vibrio harveyi can be determined in vivo by exploiting small-number fluctuations of the protein distribution when cells undergo division. When a cell divides, both its volume and LuxR protein copy number, N, are partitioned with slight asymmetries. We measured the distribution functions describing the partitioning of the protein fluorescence and the cell volume. The fluorescence distribution is found to narrow systematically as the LuxR population increases, whereas the volume partitioning is unchanged. Analyzing these changes statistically, we determined that N = 80-135 dimers at low cell density and 575 dimers at high cell density. In addition, we measured the static distribution of LuxR over a large (3000) clonal population. Combining the static and time-lapse experiments, we determine the magnitude of the Fano factor of the distribution. This technique has broad applicability as a general in vivo technique for measuring protein copy number and burst size.