Control of Genetic Parasites Mediated Through Nucleoporin Evolution

Abstract

AbstractYeasts serve as long-term hosts to several types of genetic parasites. Few studies have addressed the evolutionary trajectory of yeast genes that control the stable co-existence of these parasites with their host cell. In Saccharomyces yeasts, the retrovirus-like Ty retrotransposons must access the nucleus. We show that several genes encoding components of the yeast nuclear pore complex have experienced natural selection for substitutions that change the encoded protein sequence. By replacing these S. cerevisiae genes with orthologs from other Saccharomyces species, we discovered that natural sequence changes have affected the control of Ty retrotransposons. Specifically, changing the genetic sequence of NUP84 or NUP82 to what is found in other Saccharomyces species alters the retrotransposition of S. cerevisiae Ty1 and Ty3, respectively. Importantly, all tested housekeeping functions of NUP84 and NUP82 remained equivalent across species. The nuclear pore complex is the gatekeeper of the nucleus. It appears that nucleoporins are adapting to modulate the control of genetic parasites which access the nucleus, which is achieved despite the strict constraints imposed by host nuclear pore complex function.