Role of the RNA silencing machinery in the regulation of FLC.

迪恩实验室感兴趣的是了解是什么控制了各种植物的开花时间。我们正在使用一种模式植物拟南芥来鉴定所有参与控制开花的基因，因为在这种植物中，仅仅基于该基因的突变(病变)而不需要其他信息就可以很容易地克隆该基因。多年来，我们已经证明，在开花调控中起关键作用的是一种名为FLC的蛋白质。FLC通过停止开花所需的一组基因的激活来阻止开花。FLC水平会因冬季而降低，这就是为什么许多植物在春天开花。它还被一组基因减少，这些基因在所谓的自主促进途径中组合在一起。我们最近还发现，FLC水平受到一种新的基因调控途径的调节，涉及非常小的RNA分子。对植物中的病毒抗性和蠕虫中的发育的研究表明，长度在21到24个核苷酸之间的RNA分子充当信使，切割包含相同序列的更长的RNA分子。它们还嵌入到大型蛋白质复合体中，并引导它们找到细胞中的遗传物质(染色质=环绕在称为组蛋白的蛋白质周围的DNA)，找到具有匹配序列的DNA。涉及小RNA的过程被称为RNA沉默途径，用于人类治疗，以RNAi或RNA干扰的名义关闭基因。RNA沉默是如何被激活的，以及它是如何导致正常基因染色质结构的调节的，目前尚不清楚。我们希望通过分析FLC监管来剖析这些过程。这个系统很可能在整个生物学中产生与基因调控相关的概念。

The Dean laboratory is interested in understanding what controls the timing of flowering in a wide range of plants. We are using a model plant Arabidopsis thaliana to identify all the genes involved in controlling flowering as in this plant it is easy to clone the gene based on just having a mutation (a lesion) in that gene and no other information. Over the years we have shown that a key player in the regulation of flowering is a protein called FLC. FLC prevents flowering by stopping the activation of a set of genes needed to make flowers. FLC levels are reduced by a winter period which is why many plants flower in the spring. It is also reduced by a set of genes grouped together in the so-called autonomous promotion pathway. We have recently also found FLC levels are regulated by a new gene regulatory pathway involving very small RNA molecules. Studies on virus resistance in plants and development in worms has revealed that RNA molecules between 21 and 24 nucleotides long act as messengers to zap longer RNA molecules containing the same sequence. They also get embedded in large protein complexes and guide them to the genetic material in the cell (chromatin = DNA looped around proteins called histones) finding DNA with a matching sequence. The processes involving small RNAs have been called RNA silencing pathways and are used in human therapeutics to switch off genes under the name RNAi or RNA interference. How RNA silencing is activated and how it leads to regulation of the chromatin structure of regular genes is not known. We want to dissect these processes by analysing FLC regulation. This system is likely to produce concepts relevant to gene regulation throughout biology.