This project employs a combination of fractionation, protein labeling, and antibody techniques to identify and purify polypeptide components of pea Golgi and plasma membrane glucan synthase systems. This work makes possible the identification and cloning of the responsible gene sequences so that molecular aspects of the regulation of plant cell wall synthesis and Golgi function can be further investigated. Cell wall polysaccharides are generally the most abundant products of plant metabolism. Their biosynthesis is as characteristic and central to plant growth as structural protein synthesis is to the growth of animals. Wall synthesis must be correlated with cell enlargement; in growing tissues it is up- regulated in response to growth-stimulating hormones and environmental signals. Wall synthesis is also a prominent aspect of plant cell differentiation. Synthesis is conspicuously up- regulated during the development of thick-walled specialized cells such as epidermal cells, vascular elements, fibers and sclereids. Thus, understanding the control of wall polysaccharide-synthesizing enzymes and the genes that encode them would bring us close to the heart of plant cell biology and development.
