Identifying the Function of GLYMA10, a Potential New APC Activator

Normally, a cell's lifecycle is characterized by the growth phase followed by DNA replication and then finally cell division. This process generates genetically identical cells. Alternatively, in the process known as endoreduplication, cells grow and DNA replication occurs, but the cell does not divide. In plants, whether a cell divides normally or if it undergoes endoreduplication is dependent on CDC20 and CCS52 proteins. These two classes of proteins are anaphase promoting complex (APC) activators. In conjunction with the APC, CDC20 proteins have been found to promote normal cell division while CCS52 proteins promote endoreduplication. They do this by targeting specific proteins called cyclins, which control the progression of a cell through the cell cycle, for degradation. In soybean (Glycine max), a potential third type of APC activator, GLYMA10, has been identified. It currently has no known function, but it shares sequence similarities with CDC20 and CCS52 proteins. Like CSC20 and CCS52 proteins, GLYMA10 has defining traits such as a conserved C-box, WD40 repeats, RVL motif and an IR tail, which indicates that it may also function as an APC activator. For CDC20 and CCS52 proteins, the conserved C- box and IR tail are both needed to bind to the APC and the RVL motif found within the WD40 domain is involved with cyclin binding. To begin the process of understanding the function of GLYMA10, it will be expressed in Schizosaccharomyces pombe, a model system to study cell division, and the phenotype will be examined to determine if the gene is in fact an APC activator.