Fine-scale time-lapse analysis of the biphasic, dynamic behaviour of the two Vibrio cholerae chromosomes
Fine-scale time-lapse analysis of the biphasic, dynamic behaviour of the two Vibrio cholerae chromosomes
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DOI：
10.1111/j.1365-2958.2006.05175.x
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发表时间：
2006-06-01
影响因子：
3.6
通讯作者：
Theriot, Julie A.
中科院分区：
文献类型：
--
作者：
Fiebig, Aretha;Keren, Kinneret;Theriot, Julie A.
利用活细胞中的荧光抑制子-操纵子系统，我们研究了霍乱弧菌染色体起源的动态行为，霍乱弧菌的基因组分为两条染色体。我们已经开发出一种方法来分析细尺度运动的弯曲坐标系的弧菌细菌。使用这种方法，我们的特点是两种不同的模式的染色体行为之间的隔离事件和隔离期间。在分离事件之间，起源位置不是固定的，而是保持在椭圆形的笼状结构域内，类似于真核细胞间期染色体区域。这些结构域约为0.4 μ m宽和0.6 μ m长，反映了细胞短轴的更大限制。在分离过程中，运动是有方向性的，速度在起源之间是相当的，细胞生长可以占观察到的运动的近20%。此外，每个源的归属域由不同的机制定位。具体地，oriC（I）结构域保持在与极点的恒定实际距离处，而不管细胞长度如何，而oriC（II）结构域保持在恒定的相对位置处。因此，oriC（II）的实际位置随细胞长度而变化。虽然这两个起源的总体行为是不同的，但它们的细尺度动力学非常相似，这表明它们都经历了相似的微环境。
Using fluorescent repressor-operator systems in live cells, we investigated the dynamic behaviour of chromosomal origins in Vibrio cholerae, whose genome is divided between two chromosomes. We have developed a method of analysing fine-scale motion in the curved co-ordinate system of vibrioid bacteria. Using this method, we characterized two different modes of chromosome behaviour corresponding to periods between segregation events and periods of segregation. Between segregation events, the origin positions are not fixed but rather maintained within ellipsoidal caged domains, similar to eukaryotic interphase chromosome territories. These domains are approximately 0.4 mu m wide and 0.6 mu m long, reflecting greater restriction in the short axis of the cell. During segregation, movement is directionally biased, speed is comparable between origins, and cell growth can account for nearly 20% of the motion observed. Furthermore, the home domain of each origin is positioned by a different mechanism. Specifically, the oriC(I) domain is maintained at a constant actual distance from the pole regardless of cell length, while the oriC(II) domain is maintained at a constant relative position. Thus the actual position of oriC(II) varies with cell length. While the gross behaviours of the two origins are distinct, their fine-scale dynamics are remarkably similar, indicating that both experience similar microenvironments.