Genetic Characterization of a Yeast Nucleoporin, NUP116

Abstract

The nuclear pore complex (NPC) is being studied by several laboratories, by examining specific proteins located in this structure. Among these, a family of nucleoporins with an amino acid repeat motif of glycine-leucine-phenyl alanine-glycine (GLFG) has been the focus of research in this laboratory. A distinct region found on several of these nucleoporins (Nup145p, Nupl16p, and Nupl00p) has been shown to bind homopolymeric RNA in vitro via a novel conserved motif. Deleting NUPl16 has shown that the gene is not essential but results (nupl16∆) in temperature sensitivity with slow growth at 23°C. Further studies have shown that if the carboxyl terminus of Nupl16p (Nup116p-C) is expressed in the null background, nup116∆, there is no growth, hence, an enhanced lethality phenotype. The purpose of this study was to investigate the enhanced lethality phenotype. This phenotype was narrowed down to a 722 base pair region in the carboxyl region of NUP116-C and named NUP116-CC. Analysis by mutagenesis of NUP116-CC showed possible areas of interaction by loss of this lethal phenotype when its product is expressed in a nup116∆ strain. Additional studies of the phenotype by multicopy suppression are underway to investigate specific interactions of this region of the nucleoporin.