PDF(Pubmed)
Abstract：
The functions of closely related Myb-like repressor and Myb-like activator proteins within the plant circadian oscillator have been well-studied as separate groups, but the genetic interactions between them are less clear. We hypothesized that these repressors and activators would interact additively to regulate both circadian and growth phenotypes. We used CRISPR-Cas9 to generate new mutant alleles and performed physiological and molecular characterization of plant mutants for five of these core Myb-like clock factors compared with a repressor mutant and an activator mutant. We first examined circadian clock function in plants likely null for both the repressor proteins, CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY), and the activator proteins, REVEILLE 4 (RVE4), REVEILLE (RVE6), and REVEILLE (RVE8). The rve468 triple mutant has a long period and flowers late, while cca1 lhy rve468 quintuple mutants, similarly to cca1 lhy mutants, have poor circadian rhythms and flower early. This suggests that CCA1 and LHY are epistatic to RVE4, RVE6, and RVE8 for circadian clock and flowering time function. We next examined hypocotyl elongation and rosette leaf size in these mutants. The cca1 lhy rve468 mutants have growth phenotypes intermediate between cca1 lhy and rve468 mutants, suggesting that CCA1, LHY, RVE4, RVE6, and RVE8 interact additively to regulate growth. Together, our data suggest that these five Myb-like factors interact differently in regulation of the circadian clock versus growth. More generally, the near-norm al seedling phenotypes observed in the largely arrhythmic quintuple mutant demonstrate that circadian-regulated output processes, like control of hypocotyl elongation, do not always depend upon rhythmic oscillator function.
摘要：
植物昼夜节律振荡器中密切相关的Myb样阻遏物和Myb样激活蛋白的功能已作为单独的组进行了充分研究，但是它们之间的遗传相互作用不太清楚。我们假设这些阻遏物和激活剂会相加地相互作用以调节昼夜节律和生长表型。我们使用CRISPR-Cas9产生新的突变等位基因，并对植物突变体中的五个核心Myb样时钟因子与阻遏突变体和激活子突变体进行生理和分子表征。我们首先检查了植物中的昼夜节律时钟功能，这两种抑制蛋白可能都无效，CIRCADIAN时钟相关1（CCA1）和晚期下叶（LHY），和激活蛋白，公告4(RVE4),REVEILLE(RVE6),和REVEILLE（RVE8）。rve468三重突变体周期长，开花晚，而cca1lhyrve468五重突变体，类似于cca1lhy突变体，昼夜节律差，开花早。这表明CCA1和LHY在昼夜节律和开花时间功能上对RVE4，RVE6和RVE8具有上位性。接下来，我们检查了这些突变体中的下胚轴伸长和莲座叶大小。cca1lhyrve468突变体的生长表型介于cca1lhy和rve468突变体之间，表明CA1，LHY，RVE4、RVE6和RVE8相加地相互作用以调节生长。一起,我们的数据表明,这5种Myb样因子在昼夜节律与生长的调节中相互作用不同.更一般地说,在大部分心律失常的五重突变体中观察到的接近正常的幼苗表型表明，昼夜节律调节的输出过程，比如控制下胚轴伸长，并不总是依赖于有节奏的振荡器功能。
