Investigating the Interaction of RecQ4 and Mcm10 in Drosophila melanogaster. Wayne A. Rummings, Tim W. Christensen. Biology, East Carolina University, Greenville, NC.

   Instability of the genome through misregulation of the highly orchestrated events of the cell cycle is thought to play an important role in the development and progression of cancer and has also been implicated in the aging process. RecQ4 is one of the five RecQ helicases found in humans. It is a 1208 amino acid protein with a highly conserved Superfamily II (SFII) helicase domain that is important for maintaining cell viability. Mutations in the helicase domain of the conserved protein lead to distinct clinical diseases with increased cancer rates and premature ageing. The protein also has a unique N terminus with a 200 a.a. sequence that shares homology with yeast DNA replication initiation factor, Sld2. RecQ4 is the least characterized RecQ protein and recent studies have shown its role not only in DNA unwinding but with DNA damage repair and telomere maintenance. Given these potential roles, especially in replication, efforts have focused on elucidating specific protein-protein interactions that provide insight into the cellular processes in which RecQ4 may be involved. The mini-chromosome maintenance protein (Mcm10), a highly conserved protein first discovered in Saccharomyces cerevisiae, has essential roles in DNA replication and heterochromatin formation. Work in 293T cells and in Xenopus extracts shows a direct interaction between the two proteins with Mcm10 mediating RecQ4s association with the Mcm2-7 helicase and GINS complex. Taken together, it is of interest to determine if an interaction exists between RecQ4 and Mcm10 in the genetic model organism, Drosophila melanogaster. To confirm the interaction of the two proteins a yeast two-hybrid approach will be implemented to analyze the protein interaction. In addition genetic interactions will be tested using flies with mutations in both proteins. The use of these studies will aid in dissecting the cellular functions of these essential proteins along with increasing our understanding of the mechanisms of the disease states resulting from their associated defects.