PSEUDO-RESPONSE REGULATORS, PRR9, PRR7 and PRR5, together play essential roles close to the circadian clock of Arabidopsis thaliana
PSEUDO-RESPONSE REGULATORS, PRR9, PRR7 and PRR5, together play essential roles close to the circadian clock of Arabidopsis thaliana
复制标题
DOI：
10.1093/pcp/pci086
复制
发表时间：
2005-05-01
影响因子：
4.9
通讯作者：
Mizuno, T
中科院分区：
文献类型：
--
作者：
Nakamichi, N;Kita, M;Mizuno, T
在拟南芥中，已经鉴定了许多与时钟相关的蛋白质组分。其中，CCA 1（CIRCADIAN CLOCK-ASSOCIATED 1）/LHY（LATE ELLONGATED HYPOCOTYL）和TOC 1（TIMING OF CAB EXPRESSION 1）被认为是中央振荡器的重要组成部分。CCA 1和LHY是同源的和部分冗余的Myb相关DNA结合蛋白，而TOC 1是一个小家族的蛋白质，称为假反应调节因子。人们还认为，这两种不同类型的时钟成分在转录/翻译水平上形成了一个自动调节的正/负反馈回路，从而产生了内在节律。尽管如此，尚不确定其他PRR家族成员（PRR 9、PRR 7、PRR 5和PRR 3）是否涉及时钟功能本身。利用一组prr 9、prr 7和prr 5突变等位基因，我们建立了所有可能的单、双和三重prr突变体。他们进行了广泛的研究，通过比较他们彼此的昼夜节律，光依赖控制开花时间和光形态发生反应，红光在去黄化的表型。值得注意的是，植物中的prr 9 prr 7 prr 5三重病变导致严重的表型：（i）在连续光照条件下的心律失常，以及某些昼夜节律控制的基因的昼夜振荡的异常定相，即使在夹带的光/暗循环条件下;（ii）开花晚，对光周期性不再敏感;以及（iii）在光形态发生响应中对红光低敏感性（或盲）。单突变体和双突变体的表型也进行了广泛的表征，表明它们表现出各自的昼夜节律相关表型特征。这些结果进行了讨论的观点，PRR 9/PRR 7/PRR 5一起作为周期控制因素，他们发挥重叠和独特的作用接近（或内）的中央振荡器中，相对PRR 1/TOC 1，起着至关重要的作用。
In Arabidopsis thaliana, a number of clock-associated protein components have been identified. Among them, CCA1 (CIRCADIAN CLOCK-ASSOCIATED 1)/LHY (LATE ELONGATED HYPOCOTYL) and TOC1 (TIMING OF CAB EXPRESSION 1) are believed to be the essential components of the central oscillator. CCA1 and LHY are homologous and partially redundant Myb-related DNA-binding proteins, whereas TOC1 is a member of a small family of proteins, designated as PSEUDO-RESPONSE REGULATOR. It is also believed that these two different types of clock components form an autoregulatory positive/negative feedback loop at the levels of transcription/translation that generates intrinsic rhythms. Nonetheless, it was not yet certain whether or not other PRR family members (PRR9, PRR7, PRR5 and PRR3) are implicated in clock function per se. Employing a set of prr9, prr7 and prr5 mutant alleles, here we established all possible single, double and triple prr mutants. They were examined extensively by comparing them with each other with regard to their phenotypes of circadian rhythms, photoperiodicity-dependent control of flowering time and photomorphogenic responses to red light during de-etiolation. Notably, the prr9 prr7 prr5 triple lesions in plants resulted in severe phenotypes: (i) arrhythmia in the continuous light conditions, and an anomalous phasing of diurnal oscillation of certain circadian-controlled genes even in the entrained light/dark cycle conditions; (ii) late flowering that was no longer sensitive to the photoperiodicity; and (iii) hyposensitivity (or blind) to red light in the photomorphogenic responses. The phenotypes of the single and double mutants were also characterized extensively, showing that they exhibited circadian-associated phenotypes characteristic for each. These results are discussed from the viewpoint that PRR9/PRR7/PRR5 together act as period-controlling factors, and they play overlapping and distinctive roles close to (or within) the central oscillator in which the relative, PRR1/TOC1, plays an essential role.