Ribosomal proteins and heterogeneity of the plant ribosome

拟南芥是一种小型植物，与油菜籽属于同一科，其基因组于2000年被测序。核糖体是一台小型细胞机器，在所有细胞中协助将遗传信息转化为蛋白质。拟南芥核糖体由80个核糖体蛋白(由247个基因编码的核糖体蛋白)和4个核糖体RNA(RRNAs)组成，这些核糖体RNA分布在两个亚基中，一个大，一个小。核糖体的功能依赖于每个rp和rRNA的大致等摩尔结合。我的研究计划侧重于确定rRNA和RPS协调表达所需的信号。我对RPS S15a(S-小亚基)和L23a(L-大亚基)特别感兴趣。S15a需要首先与其rRNA结合，从而启动rRNA以添加后续的RPS，直到小亚基组装完成。L23a是所有细胞中连接核糖体大亚基和蛋白质分泌途径的一个重要的RP。与酵母和动物不同，每种植物的RP在每个细胞中都可以产生略有不同的变异(异构体)。我感兴趣的是确定什么细胞线索调节在哪个组织中产生哪个异构体，或者，如果同时产生一个以上的异构体，那么产生的植物细胞内核糖体的异质性如何影响该细胞的功能。干扰RP的产生会影响核糖体的组装和功能，因此会影响植物的生长和发育速度。因此，了解RP基因是如何调控的是更广泛的目标的一个重要方面，即如何对具有重要农学意义的作物物种的发展进行有利于我们的操纵。

Arabidopsis is a small plant, in the same family as canola, whose genome was sequenced in 2000. The ribosome is a small cellular machine that assists in the conversion of genetic information into proteins in all cells. The Arabidopsis ribosome is comprised of 80 ribosomal proteins (rps - encoded by 247 genes) and four ribosomal RNAs (rRNAs) arranged in two subunits, one large and one small. Ribosome function is dependent upon roughly equimolar association of each rp and rRNA. My research programme is focused on determining the signals required for coordinated expression of the rRNAs and rps. I am particularly interested in the rps S15a (S - small subunit) and L23a (L - large subunit). S15a is required to bind to its rRNA first and thereby prime the rRNA for the addition of subsequent rps until the small subunit is assembled. L23a is an important rp linking the large subunit of the ribosome to the protein secretary pathway in all cells. Unlike yeast and animals, slightly different variations (isoforms) of each plant rp can be made in each cell. I am interested in determining what cellular cues regulate which isoform is produced in which tissue or, if more than one isoform is produced at a time, how does the resulting heterogeneity of the ribosomes within a plant cell effect the functionality of that cell. Perturbing rp production impacts ribosome assembly and function and as such can effect the rate at which plants grow and develop. Therefore, understanding how rp genes are regulated is an important aspect of the broader goal of how the development of agronomically important crop species might be manipulated to our advantage.