The long-term goal of the proposed research is to understand the genetic control of growth and development of higher plants. The investigation focuses on the genetic control of morphogenesis in the model plant Arabidopsis thaliana. The major objective of the present study is to determine the specific roles of individual tubulin genes and tubulin isoforms in the microtubule complexes centrally involved in the processes of cell division and cell elongation that govern the morphogenesis of plant tissues and organs. The specific aims of the proposed investigations are 1) to characterize the spatial and temporal patterns of expression of individual tubulin genes by northern blot and in situ hybridization experiments, 2) to localize, spatially and temporally, the individual tubulin isoforms in developing plant tissues and organs by western blot analyses and immunofluorescence microscopy carried out with isoform-specific antibodies, 3) to use immunofluorescence microscopy and isoform- specific antibodies to determine which isoforms are present in microtubule containing structures such as preprophase bands, mitotic spindles, phragmoplasts, and the cortical arrays, 4) to identify the cis-acting sequences and trans-acting proteins and genes that control the tissue specific expression of Arabidopsis tubulin genes and 5) to utilize "overexpressed" antisense gene specific sequences in transgenic plants produced by Agrobacterium tumefaciens Ti plasmid mediated transformation to probe the function of individual tubulin genes. %%% Microtubules are filamentous polymers that play central roles in several basic processes of the cells of higher organisms. In plant cells they are involved in cell division and cell expansion, processes key to plant morphogenesis. This project is represents a detailed molecular study of the components of microtubules in plants.
