We are also investigating whether a unique, reversibly glycosylated protein is involved in cell wall biosynthesis. Again,we are employing a combination of molecular genetic, molecular biological, and cell biological approaches. These breakthroughs will permit the identification of other genes whose products are involved in this fundamental process. With the cloning of candidate genes for biosynthetic enzymes and regulatory proteins comes the challenge of determining their function. This task is particularly critical for understanding the function of numerous genes that are unique to plants and whose function cannot be predicted on the basis of sequence similarities to genes of other organisms.
Polyclonal antibodies detect homologs in both dicot and monocot species.
The patterns of expression and intracellular localization of the protein were examined. AtRGP1 protein and RNA concentration are highest in roots and suspension-cultured cells. Localization of the protein shows it to be mostly soluble but also peripherally associated with membranes. Possible sites for UDP-sugar binding and glycosylation are discussed. Our results are consistent with a role for this reversibly glycosylated polypeptide in cell wall biosynthesis, although its precise role is still unknown.