FRIMP1 and FRIMP2: novel membrane proteins required for light-regulated development of Arabidopsis

FRIMP1 和 FRIMP2：拟南芥光调节发育所需的新型膜蛋白

• 批准号: BB/E008968/1
• 负责人: Matthew Terry
• 金额: $ 50.57万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FE008968%2F1
• 关键词: FRIMP1; FRIMP2; novel; membrane; proteins

The ability of a plant to respond to its light environment is critical to its survival. Light controls many aspects of plant growth and development and is important throughout the plant life cycle. Examples of responses under the regulation of light include germination, the development of green, photosynthesizing seedlings, regulation of the architecture of the plant and control of flowering time. All of these processes are crucial to agricultural productivity and an understanding of how they are regulated has great long-term importance. Plants have a range of photoreceptors that perceive light including the phytochromes that absorb red (R) and far-red (FR) light and the cryptochromes and phototropins that respond to blue/UVA. Much of what we know about how plants respond to light has come from studies on the model plant Arabidopsis thaliana that has five phytochromes. How these phytochromes pass on their light signal to regulate plant development has been an area of great interest in recent years. We now know that in light all phytochromes relocate from the cytoplasm of the cell to the nucleus, the organelle that contains the majority of the cell's genetic information. Once in the nucleus they interact with a number of signalling proteins to change the expression of many genes that lead to changes in plant growth and development. However, this is not the full story, and there is also some biochemical and physiological evidence that phytochrome signals to proteins in the cytoplasm and in cellular membranes. To date though there is little direct genetic evidence to back up a role for membrane proteins in phytochrome regulation of plant development. We have attempted to address this anomaly by trying to identify and characterize membrane proteins with a role in light regulation of plant development. To do this we have first identified predicted membrane protein genes that are light regulated by examining data sets of all light-regulated genes in Arabidopsis. Using this approach we have identified a number of membrane transporter genes that appear to have a role in seedling development. We have also identified some membrane proteins of unknown function and one of these is a FR light-induced membrane protein we have called FRIMP1. FRIMP1 and its close counterpart, FRIMP2, appear to be important for both seedling development and leaf development in Arabidopsis. We have identified frimp1 and frimp2 mutants that lack the FRIMP1 and FRIMP2 proteins and these mutants show a long hypocotyl under FR light and large cotyledons under R light, indicating that FRIMP1 and FRIMP2 are required for normal development of these plant tissues in the light. Interestingly, the FRIMP proteins are members of a completely new membrane protein family with close relatives in all multicellular eukaryotes including humans. As they have not been investigated in any of these organisms, what we learn about them in plants may be of much broader significance. The main aim of this project is to understand the function of FRIMP1 and FRIMP2 in response to light by determining all of the physiological processes they regulate and where they are located. We will do this by examining in detail the physiological responses of the frimp1 and frimp2 mutants, a frimp1frimp2 double mutant we have produced, and plants in which the levels of FRIMP1 and FRIMP2 proteins have been artificially increased. This will tell us the full range of responses in which FRIMP1 and FRIMP2 are involved. We will also determine what genes show altered expression in frimp1 and frimp2 mutants and use this information to find out how FRIMP1 and FRIMP2 interact with different signalling pathways within the plant. Finally, we will use two types of reporter proteins to show where FRIMP1 and FRIMP2 are located in the plant and also where they are within the cell. We will then be in a position to develop testable hypotheses about how FRIMP1 and FRIMP2 function at the molecular level.

植物对光环境的反应能力对其生存至关重要。光控制着植物生长和发育的许多方面，在植物的整个生命周期中都很重要。在光调节下的响应的实例包括发芽、绿色的发育、光合作用幼苗、植物结构的调节和开花时间的控制。所有这些过程对农业生产力都至关重要，了解它们是如何受到监管的具有重要的长期意义。植物具有一系列感知光的光感受器，包括吸收红色（R）和远红色（FR）光的光敏色素以及响应蓝色/UVA的隐花色素和向光蛋白。我们对植物如何对光做出反应的了解，大部分来自对模式植物拟南芥的研究，拟南芥有五种光敏色素。这些光敏色素如何传递光信号来调节植物的发育是近年来研究的热点。我们现在知道，在光照下，所有光敏色素都从细胞质转移到细胞核，细胞核是包含细胞大部分遗传信息的细胞器。一旦进入细胞核，它们就与许多信号蛋白相互作用，改变许多基因的表达，从而导致植物生长和发育的变化。然而，这并不是全部的故事，也有一些生化和生理证据表明光敏色素信号在细胞质和细胞膜中的蛋白质。迄今为止，虽然有很少的直接遗传证据支持的作用，膜蛋白在植物生长的光敏色素调节。我们试图解决这个异常现象，试图确定和表征膜蛋白在植物发育的光调节的作用。为了做到这一点，我们首先确定了预测的膜蛋白基因，通过检查数据集的所有光调节基因在拟南芥中的光调节。使用这种方法，我们已经确定了一些膜转运蛋白基因，似乎有一个在幼苗发育的作用。我们还鉴定了一些功能未知的膜蛋白，其中之一是FR光诱导的膜蛋白，我们称之为FRIMP 1。FRIMP 1和它的紧密对应物FRIMP 2似乎对拟南芥的幼苗发育和叶片发育都很重要。我们已经鉴定了缺乏FRIMP 1和FRIMP 2蛋白的frimp 1和frimp 2突变体，并且这些突变体在FR光下显示长的下胚轴，在R光下显示大的子叶，表明FRIMP 1和FRIMP 2是这些植物组织在光下正常发育所需的。有趣的是，FRIMP蛋白是一个全新的膜蛋白家族的成员，在包括人类在内的所有多细胞真核生物中都有近亲。由于它们尚未在这些生物中进行过研究，因此我们在植物中了解到的它们可能具有更广泛的意义。该项目的主要目的是通过确定FRIMP 1和FRIMP 2调节的所有生理过程以及它们的位置来了解FRIMP 1和FRIMP 2响应光的功能。我们将通过详细研究frimp 1和frimp 2突变体、我们生产的frimp 1frimp 2双突变体以及人工增加FRIMP 1和FRIMP 2蛋白水平的植物的生理反应来做到这一点。这将告诉我们FRIMP 1和FRIMP 2参与的全部反应范围。我们还将确定哪些基因在frimp 1和frimp 2突变体中表现出改变的表达，并利用这些信息来了解FRIMP 1和FRIMP 2如何与植物内不同的信号通路相互作用。最后，我们将使用两种类型的报告蛋白来显示FRIMP 1和FRIMP 2在植物中的位置以及它们在细胞内的位置。然后，我们将能够开发关于FRIMP 1和FRIMP 2如何在分子水平上发挥作用的可验证的假设。