CIRCADIAN CLOCK ASSOCIATED1 and LATE ELONGATED HYPOCOTYL Function Synergistically in the Circadian Clock of Arabidopsis
CIRCADIAN CLOCK ASSOCIATED1 and LATE ELONGATED HYPOCOTYL Function Synergistically in the Circadian Clock of Arabidopsis
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DOI：
10.1104/pp.108.133272
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发表时间：
2009-06-01
期刊：
影响因子：
7.4
通讯作者：
Tobin, Elaine M.
中科院分区：
文献类型：
--
作者：
Lu, Sheen X.;Knowles, Stephen M.;Tobin, Elaine M.
生物钟是一种内源性机制，可协调生物过程与环境的日常和季节变化。中央时钟组件的异二聚化是控制几种不同昼夜节律系统中时钟功能的重要方式。昼夜节律时钟相关蛋白 1 (CCA1) 和晚伸长下胚轴 (LHY) 是 Myb 相关蛋白，在拟南芥 (Arabidopsis thaliana) 的中央振荡器内或附近发挥作用。 cca1 和 lhy 的单突变体具有短周期节律的表型。 cca1 lhy 双突变体显示出比 cca1 单突变体更短的周期表型，表明 CCA1 和 LHY 仅部分功能冗余。为了确定 CCA1 和 LHY 在生物钟中是否并行或协同作用，我们检查了它们在光照生长和黄化幼苗中的表达。我们已经证明，LHY 和 CCA1 与光捕获叶绿素 a/b 蛋白（Lhcb，也称为 CAB）启动子的相同区域结合。 CCA1和LHY可以形成同二聚体，并且它们也在细胞核中共定位并在体外和体内形成异二聚体。在拟南芥中，CCA1 和 LHY 以独立于光周期的方式发生物理相互作用。此外，凝胶过滤色谱的结果表明CCA1和LHY存在于植物中的同一大复合物中。综上所述，这些结果表明 CCA1 和 LHY 在调节拟南芥昼夜节律方面发挥协同作用。
The circadian clock is an endogenous mechanism that coordinates biological processes with daily and seasonal changes in the environment. Heterodimerization of central clock components is an important way of controlling clock function in several different circadian systems. CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) are Myb-related proteins that function in or close to the central oscillator in Arabidopsis (Arabidopsis thaliana). Single mutants of cca1 and lhy have a phenotype of short-period rhythms. cca1 lhy double mutants show an even shorter period phenotype than the cca1 single mutant, suggesting that CCA1 and LHY are only partially functionally redundant. To determine whether CCA1 and LHY act in parallel or synergistically in the circadian clock, we examined their expression in both light-grown and etiolated seedlings. We have shown that LHY and CCA1 bind to the same region of the promoter of a Light-harvesting chlorophyll a/b protein (Lhcb, also known as CAB). CCA1 and LHY can form homodimers, and they also colocalize in the nucleus and heterodimerize in vitro and in vivo. In Arabidopsis, CCA1 and LHY physically interact in a manner independent of photoperiod. Moreover, results from gel filtration chromatography indicate that CCA1 and LHY are present in the same large complex in plants. Taken together, these results imply that CCA1 and LHY function synergistically in regulating circadian rhythms of Arabidopsis.