U.S.-Austria Cooperative Research: A Model for Plastid Evolution--Cyanophora Cyanelle DNA (Molecular Biology)

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This award will support a two-year cooperative research project between Professor Hans J. Bohnert, Department of Biochemistry, University of Arizona, and Dr. Wolfgang Loeffelhardt, Institute for General Biochemistry, University of Vienna, Austria. The scientists and members of their research groups will study the genome and gene structure of cyanelle DNA from Cyanophora paradoxa. They will attempt to determine (1) the structure of several genes/operons on cyanelle DNA which are differently organized in cyanelle and higher plant chloroplast DNA and (2) the extent to which the cyanelle is dependent on import of proteins from the surrounding cytoplasm and how this transport is achieved, either differently from or identically to the transport in higher plants. The long-term goal of the work is to understand, by monitoring differences between the well-studied higher plant chloroplast characteristics and the cyanelle genome, which evolutionary options were available to permit a photosynthetically active organelle to be integrated into the metabolism of a eukaryotic cell. The cyanelle in Cyanophora paradoxa is an example of a plastid, a membrane-enclosed component of a plant cell. Chloroplasts in leaves are another, better-known example. In this study, the cooperating scientists will carry out biochemical and molecular biological studies aimed at demonstrating the degree of relatedness of cyanelle genes to those in higher plant chloroplasts and to cyanobacterial genes. The work involves sequencing several cyanelle chromosome regions selected for their anticipated value in making these comparisons. In this way it may be possible to gather evidence for the evolution of specific genes from simple bacteria through Cyanophora paradoxa to still higher plants, such as trees. Professor Bohnert is experienced in molecular biology and plant genetics. Professor Loeffelhardt is a biochemist with experience in working with the proteins to be studied in these experiments. Their expertise will be combined in a study which is expected to shed light on the evolution of genes that are located in different cellular compartments in an organism whose evolutionary history is not well understood.