We have recently discovered and characterized a gene encoding a new plant structural protein (ptGRP1) whose predicted amino acid composition contains 67% glycine. ptGRP1 was the fourth class of structural protein to be identified in plants. The predicted protein structure and immunochemical studies indicated that the ptGRP1 protein product functions as a cell wall structural protein. This gene, on both the transcriptional and gene product levels, is developmentally regulated and shows increased expression after wounding. This proposal proposes to determine immunocytochemically the exact cell specificity of this gene in all organs and the temporal pattern of ptGRP1 deposition in each of these cell types during development. In addition experiments to phenotypically characterized the effects of over-and under-expression of the ptGRP1 gene are proposed. This study should provide information which will help to determine the function of this gene and the contribution it makes to the development and morphology of the plant as a whole.