Expression of Calcium binding Protein Genes in Arabidopsis

All eukaryotes utilize changes in the concentration of free calcium ions (Ca ²⁺) as a signal to initiate a cascade of metabolic changes that results in altered development, growth, or physiological function. A primary intracellular target for Ca ²⁺ acting as second messengers in this cascade system are the calcium (Ca)-modulated proteins. In animals, a number of members of the CA-modulated protein family have been identified and their physiological roles are well understood. Plants on the other hand, boast of only one well-characterized Ca-modulated protein, calmodulin (CaM), whose physiological functions are much less clearly defined. Professor Zielinski and his team have recently shown, by cDNA cloning experiments, that plants contain at least two different isomeric forms of CaM, as well as at least one additional structurally related Ca ²⁺-binding protein. This proposal is aimed at improving the understanding of how these proteins participate in plant growth and development, by analyzing where, and to what extent, they are expressed in the organ systems of Arabidopsis thaliana. The long-range goal of this work is to identify all the members of the Ca-modulated protein family in plants by recombinant DNA technology, and to determine what physiological roles these proteins play in plant growth and development.