Biogenesis of the plant ribosome and its role in plant growth and development

拟南芥是一种小植物，与油菜籽属于同一科。核糖体是一种天然的纳米机器，存在于所有活细胞中，负责将存储在细胞核中的DNA信息转化为能够在细胞、组织或有机体内工作的蛋白质。核糖体的两个亚基(大的：LSU和小的：SSU)本身是由位于核糖体RNA(RRNA)内部支架上的蛋白质组成的--就像房屋框架上的壁板、窗户和门。我的研究重点是了解拟南芥中的核糖体生物发生，以及它如何影响整个植物的生长和发育。 拟南芥核糖体主要由81种不同的核糖体蛋白(RPS)各一个拷贝组成。在2-7个成员的家庭中，81个RP的每个基因都存在于核基因组中。每个家族成员产生其编码的RP的一个变体(异构体)，使得一个7个成员的家族可以产生相同蛋白质的7个异构体，但该蛋白质的一个异构体只能是任何一个核糖体的一部分。在拟南芥中，这种基因与蛋白质的比例可以产生高达100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000种核糖体蛋白质组成的变异。我的实验室正在努力回答的两个问题是：为什么植物需要动物和酵母中不存在的核糖体组成的异质性水平？一个RP异构体的缺失或一个RP家族的缺失对植物的生长发育有什么影响？ 核糖体的LSU和SSU的rRNA和RPS组装在核仁中，核仁是细胞核内合成rRNA的小区域。然而，RPs是在细胞质中合成的，必须穿过核膜运输到细胞核，然后进入核仁，在那里它们组装在LSU和SSU rRNA上。我们正在确定这种RP运输以及随后的LSU和SSU在核仁中组装的机械性要求。 一旦我们了解了植物核糖体的生物发生，我们能否对这个天然的纳米机器进行修补，并让它在植物细胞内执行我们的命令？

Arabidopsis is a small plant, in the same family as canola. A ribosome is the natural nano machine, found in all living cells, that is responsible for the conversion of the information stored as DNA in the nucleus, into proteins capable of doing work within the cell, tissue or organism. The two subunits (large: LSU and small: SSU) of a ribosome are themselves comprised of proteins located on an internal scaffold of ribosomal RNA (rRNA) - like the siding, windows and doors on the framing of a house. My research programme is focused on understanding ribosome biogenesis in Arabidopsis, and how it effects overall plant growth & development. The Arabidopsis ribosome is primarily comprised of one copy of each of 81 different ribosomal proteins (rps). Genes for each of the 81 rps are present in the nuclear genome in families of between 2-7 members. Each family member produces a variation (isoform) of the rp that it encodes, such that a family of 7 members can produce 7 isoforms of the same protein, but only one isoform of this protein can be part of any one ribosome. In Arabidopsis, this gene to protein ratio could produce up to 100,000,000,000,000,000,000,000,000,000 variations in ribosome protein composition. Two questions my lab is working to answer are: Why do plants require a level of heterogeneity in ribosome composition that is not present in animals and yeast? What effects does the loss of one rp isoform or the loss of a single rp family have on plant growth & development? The rRNA and rps of the LSU and SSU of the ribosome are assembled in the nucleolus, a small region within the nucleus of the cell, where rRNA is synthesised. However, rps are synthesised in the cytoplasm of the cell and have to be transported across the nuclear membrane into the nucleus and then the nucleolus, where they assemble on the LSU and SSU rRNA. We are in the process of identifying the mechanistic requirements for this rp transport and subsequent LSU and SSU assembly in the nucleolus. Once we understand plant ribosome biogenesis, could we tinker with this natural nano machine and make it do our bidding within the plant cell?