Analyzing the Ability of Differing FG Domains to Rescue the Gle1-Dbp5 Interaction

Analyzing the Ability of Differing FG Domains to Rescue the Gle1-Dbp5 Interaction Lauren Brown, Rebecca Adams, PhD In order for proteins to be made in eukaryotic cells, mRNA must first be exported from their site of production in the nucleus through the nuclear pore complex (NPC) to reach the cytoplasm. To cross through the NPC, mRNA binds to a transport protein called Mex67 which is able to bind NPC proteins to allow passage of the mRNA. Once in the cytoplasm, Mex67 is removed by Dbp5. Without Mex67 bound, mRNA cannot re-enter the nucleus, ensuring the directionality of mRNA export. Dbp5 is an enzyme that has ATPase activity that is essential for Mex67 removal. The function of Dbp5 is regulated by its interaction with the protein Gle1, and the Dbp5-Gle1 interaction is dependent on the NPC protein Nup42. The N-terminus of Nup42 is an FG domain that binds to Mex67, and the Nup42 C-terminus binds to Gle1. Previous experiments have shown that the Nup42 FG domain is required for the Gle1-Dbp5 interaction. We hypothesize that this is due to the interaction of this domain with Mex67. To test this, the goal of my work is to test if FG domains found in other NPC proteins can restore the Gle1-Dbp5 interaction via a yeast two-hybrid (Y2H) assay. Thus far, we have recapitulated the Gle1-Dbp5 interaction, and ongoing experiments are exploring Nup42 constructions for their contribution to this interaction. Keywords: Saccharomyces cerevisiae, yeast two-hybrid, mRNA export, Gle1-Dbp5, Nup42 FG domains, Mex6