9317526 Harada The long range scientific role of this project is to obtain a mechanistic understanding of the processes that specify the function and structure of glyoxysomes, subcellular organelles that compartmentalize critical metabolic reactions in a cell. In this proposal, two key questions about glyoxysome formation are considered. First, how is the induction of glyoxysomal function regulated during plant development? This question will be addressed by dissecting the processes regulating genes encoding two glyoxysome-specific enzymes, isocitrate lyase and malate synthase, that are required for glyoxysomal function. Previous studies from this lab established that transcriptional processes play the primary role in regulating accumulation of these enzymes in glyoxysomes. Therefore, a mechanistic understanding of the processes regulating expression of these two genes will provide insight into the physiological signal(s) and pathway(s) that control glyoxysomal function during plant development. The second key question will focus on glyoxysome assembly. What are the genes that are required to establish the structure of the organelle and to import proteins into peroxisomes, and how are these genes regulated during development? Genes involved in glyoxysome assembly will be identified by selecting plant cDNA clones that complement mutants of Saccharomyces cerevisiae. In the long term, these approaches will provide a global overview of the processes involved in glyoxysome formation. The proposed studies will provide significant basic information about the processes that establish an organelle's structure and function. Furthermore, infomation obtained from these studies may be directly applicable to the design of strategies to improve crop plants using genetic engineering protocals. ***
