ROLE OF THE ANTIZYME FAMILY DURING XENOPUS DEVELOPMENT

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Polyamines are charged organic molecules that are vitally important for macromolecular reactions in cells but are toxic at high levels. There exist well-regulated biosynthetic pathways for both polyamine anabolism and catabolism. A protein involved in the control of polyamine levels, antizyme (AZ), plays a role in regulating polyamine levels in cells. AZ lowers polyamines below toxic levels by inhibiting polyamine uptake and activity of the rate-limiting enzyme ornithine decarboxylase (ODC) via direct binding and targeted degradation of ODC. By understanding the function of AZ in a normal setting, one can better understand the role of AZ in a disease setting and determine the nature of its toxicity in controlling cell proliferation. A tractable organism for polyamine research is the budding yeast Saccharomyces cerevisiae. The regulation of polyamine synthesis in yeast has been delineated although not specifically the role of antizyme in the process. In addition, mammalian forms of the polyamine genes can complement their functional equivalents in yeast cells. Using a yeast genetic screen, genes that functionally interact with AZ and its regulation of ODC can be isolated and characterized. This study proposes to use a genetic screen to obtain yeast genes that play a role in the regulation and function of the ODC/AZ pathway in yeast. A strain has been designed that is dependent on ODC enzymatic activity for viability. Expression of antizyme results in induced lethality due to lowered levels of polyamines. We hope to isolate yeast genes that can interact with the polyamine pathway and revert the lethal phenotype.