Localization of Mini-chromosome Maintenance Protein 10. Nicholas W. Faulkner, Tim W. Christensen. East Carolina University, Greenville, NC.

   In order for organisms to maintain homeostasis, it is vital for DNA to replicate with high fidelity. Failure to do so will leave uncorrected mistakes, which have the capacity to cause lethal mutations, cancerous growth, or disease. Mini-chromosome maintenance protein 10 (Mcm10), a key component of replication initiation, was first identified in Saccharomyces cerevisiae, is highly conserved across species, and is postulated to form a homohexameric ring. Structurally, Mcm10 contains an N-terminal self-binding site, DNA and Pol binding sites on the internal domain, and DNA and Pol binding sites on the C-terminal domain. Moreover, Mcm10 has been shown to associate with pre-initiation and elongation complexes. Recent studies however, have demonstrated that Mcm10 may have alternative functions including chromatin remodeling, as hypomophic mutants suppress position effect variegation. The role for Mcm10 in heterochromatin formation may be through its interaction with heterochromatin protein 1. Despite two decades of research, the exact role of Mcm10 remains elusive, likely due to Mcm10's multiple cellular roles. To further understand these possible roles, it is of interest to investigate the localization of Mcm10, both spatially and temporally. To achieve this, a combination of approaches will be taken including; immunofluorescence, live-cell imaging, and western blots. Localization studies of Mcm10 will be carried out in both wild-type and multiple Mcm10 mutant backgrounds, of which chromatin defects, lethality, or sterility are displayed. Furthermore, localization will be studied in endoreplicating tissues, meiotic tissues, and cell lines in an effort to clarify Mcm10's possible roles. These localization studies will likely help in understanding the wide variety of Mcm10 mutant phenotypes and, in combination with future co-localization experiments, will allow the assignment of these phenotypes to interactions with specific proteins. Taken together, knowledge of the roles and mechanisms of Mcm10 make it an attractive therapeutic target for cancer and replication associated disease.