Hall Anthony, Kozma-Bognár László, Bastow Ruth M, Nagy Ferenc, Millar Andrew J
Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
Plant J. 2002 Nov;32(4):529-37. doi: 10.1046/j.1365-313x.2002.01441.x.
Phytochrome B (phyB) is a major phytochrome active in light-grown plants. The circadian clock controls the expression of the PHYB gene. We have used the luciferase reporter gene (LUC) to monitor the rhythmic expression of PHYB in photoreceptor and clock-associated mutant backgrounds. Surprisingly, we found that PHYB and CAB expression have different free-running periods, indicating that separate circadian clocks control these genes. The effects of mutations show that the clocks share common components. This suggests that they are copies of the same clock mechanism in different locations, most likely in different cell layers. Furthermore, we show that phyB is required for a negative feedback loop that strongly antagonises the expression of PHYB. Compared to a system with only one clock, this regulatory complexity might allow the phase of peak expression for one clock-controlled gene to alter, relative to other genes or to changing environmental conditions.
光敏色素B（phyB）是在光照生长的植物中起主要作用的一种光敏色素。生物钟控制着PHYB基因的表达。我们利用荧光素酶报告基因（LUC）来监测在光受体和与生物钟相关的突变背景下PHYB的节律性表达。令人惊讶的是，我们发现PHYB和CAB的表达具有不同的自由运转周期，这表明不同的生物钟控制着这些基因。突变的影响表明这些生物钟共享共同的组件。这表明它们是同一生物钟机制在不同位置的拷贝，很可能在不同的细胞层。此外，我们表明phyB对于一个强烈拮抗PHYB表达的负反馈环是必需的。与只有一个生物钟的系统相比，这种调控的复杂性可能允许一个生物钟控制基因的表达峰值阶段相对于其他基因或不断变化的环境条件发生改变。
