Cellulose synthesis and regulation in plants.

植物细胞壁是一种复杂的动态结构，在植物生长发育中起着重要作用。如果不考虑植物细胞壁的情况，就不可能考虑植物细胞或构成植物的细胞纲要。因此，要更好地了解植物如何发育和生长，就需要了解控制细胞壁组装和完整性的机制。虽然细胞壁由许多不同的糖聚合物组成，但主要的承重聚合物是纤维素。尽管它的丰富和多年的研究，我们的知识纤维素是如何制作和整合到不断增长的墙壁仍然非常有限。我的研究计划的主要目标是解决纤维素是如何合成的，以及如何调节这一过程。为了确定纤维素生物合成的机制，我们利用两个模型系统：一个细菌，木葡糖酸醋杆菌，和一个植物，拟南芥。细菌系统的优点是，纤维素合成酶的活性可以很容易地在体外测量，这是迄今为止在植物中很难做到的。而拟南芥是服从遗传分析，这使我们能够从遗传学角度剖析植物中的纤维素生物合成。这两个系统将用于实现三个短期目标：（1）确定纤维素合成酶蛋白质的结构-功能关系，（2）分析纤维素合成酶复合物结构和（3）鉴定潜在的纤维素合成酶调节剂。结合遗传分析，我们将使用现代细胞生物学和生物化学技术来实验性地实现这些目标。对纤维素生物合成的深入了解将为理解长链聚合物在自然界中是如何形成的提供基础。此外，这些知识可以应用于创建或修改天然聚合物。纤维素的特性，如影响木材质量的微纤丝角、聚合度（葡萄糖单元数）及其结晶度都具有经济意义。

The cell wall of plants is a complex and dynamic structure with many important roles in plant growth and development. It is impossible to consider a plant cell or the compendium of cells that make up a plant, if not in the context of their cell walls. Gaining a better understanding of how plants develop and grow therefore requires a knowledge of the mechanisms that control both cell wall assembly and integrity. Although the cell wall is made up of many different sugar polymers, the primary load-bearing polymer is cellulose. Despite its abundance and a number years of study, our knowledge of how cellulose is made and integrated into the growing wall is still very limited. The principle aims of my research program are to address how cellulose is synthesized and how this process is regulated. To determine the mechanisms of cellulose biosynthesis we are utilizing two model systems: a bacterium, Gluconoacetobacter xylinus, and a plant, Arabidopsis. The bacterial system has the advantage that cellulose synthase activity can be easily measured in vitro, something that has, so far, been difficult in plants. While Arabidopsis is amenable to genetic analysis, which allows us to genetically dissect cellulose biosynthesis in a plant. These two systems will be used to achieve three short-term objectives: (1) determine the structure-function relationships of cellulose synthase proteins, (2) analyze cellulose synthase complex structure and (3) identify potential cellulose synthase regulators. In combination with genetic analysis we will use modern cell biological and biochemical techniques to experimentally reach these goals. A deeper understanding of cellulose biosynthesis will provide the basis for understanding how long chain polymers are made in nature. In addition, this knowledge can be applied to creating or modifying natural polymers. Features of cellulose such as microfibril angle, which affects wood quality, the degree of polymerization (number of glucose units), and it’s crystallinity are all of economic interest.